KR20020087295A - Photosensitive polymer including copolymer of alkyl vinyl ether and furanone and resist composition comprising the same - Google Patents

Abstract

PURPOSE: A photoresist polymer and a resist composition containing the polymer are provided, to improve the resistance against the dry etching of resist, the adhesive property to under substrate and the stability to moisture. CONSTITUTION: The photoresist polymer comprises a copolymer of an alkyl vinyl ether and furanone, represented by the formula 1, wherein R1 and R2 are H or an alkyl group of C1-C3, respectively; and X is a linear alkyl vinyl ether represented by -CH(R3)-CH(OR4)- or a cyclic alkyl vinyl ether represented by the formula 2(wherein R3 is H or methyl group; R3 is a hydrocarbon group of C1-C20; y is an integer of 1-4; and R5 is H or an alkyl or alkoxy group of C1-C3). The resist composition comprises a photosensitive polymer which is obtained by copolymerizing the copolymer of an alkyl vinyl ether and furanone, and a comonomer having a substituent or polar functional group capable of being degraded by an acid; and a photoacid generator.

Description

Photosensitive polymer including copolymer of alkyl vinyl ether and furanone and resist composition comprising the same {Photosensitive polymer including copolymer of alkyl vinyl ether and furanone and resist composition comprising the same}

The present invention relates to photosensitive polymers and chemically amplified resist compositions, and more particularly to photosensitive polymers comprising copolymers of alkyl vinyl ethers, and resist compositions comprising the same.

As the manufacturing process of semiconductor devices 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), which is a new energy exposure source, has emerged.

Common ArF resist compositions known to date have primarily used acrylic or methacrylic polymers. Among them, methacrylate copolymers having an alicyclic protecting group having the following structure have been proposed.

In the methacrylate backbone of the copolymer having the above structure, an adamantyl group for increasing resistance to dry etching and a lactone group for improving adhesive properties were introduced. As a result, excellent results were obtained in terms of the resolution and depth of focus of the resist, but still poor resistance to dry etching. Further, when the line pattern is formed from the resist film obtained therefrom, line edge roughness is severely observed. In addition, there is a problem that the manufacturing cost of the raw material (raw material) used to obtain a polymer having the same structure is very high.

As a polymer used in the resist composition according to another prior art, it has been proposed to consist of a cycloolefin-co-maleic anhydride (COMA) alternating polymer having the following structure.

The COMA alternating copolymer of the above structure has the advantage that the resistance to dry etching is improved and the manufacturing cost of the raw material is low, but the resolution is inferior. In addition, the norbornene structure included in the backbone provides very large rigidity, which makes it difficult to proceed with the process using it.

Recently, polymers having various structures have been proposed to improve the above problems. A representative example thereof is a vinyl ether-co-maleic anhydride (VEMA) copolymer having a vinyl ether monomer unit having the following structure.

In the formula, R is an alicyclic group decomposable by acid. Since the VEMA copolymer has a backbone that is relatively flexible compared to the COMA copolymer, the process proceeds more smoothly.

However, as described above, the COMA copolymer and the VEMA copolymer containing the maleic anhydride monomer unit have unstable properties with respect to water content. That is, when stored for a long time in the state containing water in the resist, there is a problem that the structure of maleic anhydride is changed to maleic acid, which is an acid structure, to degrade the performance of the resist . Moreover, when it contains the maleic anhydride in excess, it has the property to absorb the 193 nm wavelength which is the wavelength of ArF excimer laser excessively. Thus, the transmittance of the resist is reduced resulting in a decrease in resolution.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive polymer having a structure capable of increasing resistance to dry etching and adhesion to a lower film quality when used as a raw material of a resist and at the same time having a stable property against moisture.

It is another object of the present invention to provide excellent resistance to dry etching and adhesion to the underlying film, excellent storage stability, and high resolution photolithography properties in a photolithography process using light sources having wavelengths of 193 nm and 248 nm. It is to provide a resist composition.

In order to achieve the above object, the photosensitive polymer according to an aspect of the present invention includes a copolymer of alkyl vinyl ether and furanone represented by the following formula.

Wherein R ₁ and R ₂ are each a hydrogen atom or an alkyl group of C ₁ to C ₃ , and X is a linear or cyclic alkyl vinyl ether having any one structure selected from the structures shown below.

And

Of the above formulas, R ₃ is a hydrogen atom or a methyl group, R ₄ is C ₁ ~ hydrocarbon group of C _20, y is an integer of 1 ~ 4, R ₅ is a hydrogen atom, or C ₁ ~ alkyl group of C ₃ or It is an alkoxy group.

Preferably, R ₄ is a methyl group, an ethyl group, 2-hydroxy ethyl group, n-butyl group or iso-butyl group.

Also, preferably, R ₅ is a methoxy group or an ethoxy group.

In order to achieve the above object, the photosensitive polymer according to another aspect of the present invention is (a) a copolymer of alkyl vinyl ether and furanone represented by the following formula, and (b) a substituent or polar functional group which can be decomposed by an acid. comonomers having a (polar functional group) are copolymerized.

Wherein R ₁ and R ₂ are as defined above and X is a linear or cyclic alkyl vinyl ether having any of the structures selected from the structures shown below.

And

In the formulas, R ₃ , R ₄ , R ₅ and y are as defined above.

Preferably, the comonomer consists of an acrylate derivative or a methacrylate derivative. In this case, the photosensitive polymer may be represented by the following equation.

Wherein R ₆ is a hydrogen atom or a methyl group, R ₇ is a C ₂ to C ₂₀ hydrocarbon group which can be decomposed by acid, m / (m + n) = 0.1 to 0.9, n / (m + n ) = 0.1 to 0.9.

R ₇ may be a t-butyl group or a tetrahydropyranyl group.

Alternatively, R ₇ is a substituted or unsubstituted alicyclic hydrocarbon group, for example, 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 8-ethyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 2- Methyl-2-adamantyl, 2-ethyl-2-adamantyl, 1-adamantyl-1-methylethyl, 2-methyl-2-pentyl or 2-ethyl-2-pentyl group.

In order to achieve the above another object, the resist composition according to the present invention is (a) (a-1) a copolymer of alkyl vinyl ether and furanone represented by the following formula, (a -2) a photosensitive polymer formed by copolymerization of a comonomer having a substituent or a polar functional group that can be decomposed by an acid, and (b) a photoacid generator (PAG).

Wherein R ₁ and R ₂ are each a hydrogen atom or an alkyl group of C ₁ to C ₃ , and X is a linear or cyclic alkyl vinyl ether having any one structure selected from the structures shown below.

And

Of the above formulas, R ₃ is a hydrogen atom or a methyl group, R ₄ is C ₁ ~ hydrocarbon group of C _20, y is an integer of 1 ~ 4, R ₅ is a hydrogen atom, or C ₁ ~ alkyl group of C ₃ or It is an alkoxy group.

Preferably, the comonomer consists of an acrylate derivative or a methacrylate derivative.

It is preferable that the weight average molecular weights of the said photosensitive polymer are 1,000-100,000.

The PAG is included in an amount of 1 to 15% by weight based on the weight of the photosensitive polymer.

Preferably, the PAG consists of triarylsulfonium salts, diaryliodonium salts, sulfonates or mixtures thereof. Particularly preferred, the PAG is triphenylsulfonium triflate, triphenylsulfonium antimonate, diphenyliodonium triflate, diphenyliodonium antimo Diphenyliodonium antimonate, methoxydiphenyliodonium triflate, di-t-butyldiphenyliodonium triflate, 2,6-dinitrobenzyl sulfonate ( 2,6-dinitrobenzyl sulfonates, pyrogallol tris (alkylsulfonates), N-hydroxysuccinimide triflate, norbornene-dicarboximide-tree Plates (norbornene-dicarboximide-triflate), triphenylsulfonium nonaflate, diphenyliodonium nonaflate, methoxydipe Ionicdiphenyliodonium nonaflate, di-t-butyldiphenyliodonium nonaflate, N-hydroxysuccinimide nonaflate, norbornene -Norcarne-dicarboximide-nonaflate, triphenylsulfonium perfluorooctanesulfonate (PFOS), diphenyliodonium PFOS, methoxydiphenyliodo Methoxydiphenyliodonium PFOS (di-t-butyldiphenyliodonium triflate), N-hydroxysuccinimide PFOS (N-hydroxysuccinimide PFOS), norbornene-dicarboxyi Mid PFOS (norbornene-dicarboximide PFOS), or mixtures thereof.

The resist composition according to the present invention may further comprise an organic base. The organic base is included in an amount of 0.01 to 2.0% by weight based on the weight of the photosensitive polymer.

Preferably, the organic base consists of a compound consisting of tertiary amines alone or by mixing two or more kinds. More preferably, the organic base is triethylamine, triisobutylamine, triisooctylamine, triisodecylamine, diethanolamine, diethanolamine, triethanolamine ( triethanolamine, N-alkyl substituted pyrrolidinone, N-alkyl substituted caprolactam, N-alkyl substituted valerolactam or It consists of a mixture.

The resist composition according to the present invention may further contain 30 to 200 ppm of a surfactant.

The photosensitive polymer according to the present invention has a structure capable of increasing resistance to dry etching and adhesion to the underlying film and at the same time has a stable property against moisture. The resist composition according to the present invention obtained from such a photosensitive polymer not only has excellent resistance to dry etching and adhesion to the underlying film, but also has excellent storage stability and can exhibit excellent high-resolution lithography performance.

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

The photosensitive polymer according to the present invention has a basic structure including an alternating copolymer of alkyl vinyl ether and furanone having a linear or cyclic structure. Such a basic structure is copolymerized with a monomer unit having a photosensitive substituent such as an acrylate or methacrylate monomer unit to have a function as a photosensitive polymer. Copolymers of alkyl vinyl ethers with furanone can be easily obtained by general radical polymerization by mixing 1: 1 alkyl vinyl ethers and furanone compounds. At this time, bulk polymerization or solution polymerization is used. As the initiator, a general radical initiator such as abisoisobutyronitrile (AIBN), lauroyl peroxide or the like can be used. In solution polymerization, it is possible to use polar solvents such as tetrahydrofurane (THF), dioxane and the like, or nonpolar solvents such as cyclohexane and the like.

Example 1

Synthesis of Copolymer

After dissolving 4.2 g of furanone and 3.5 g of dihydrofuran in 7 g of dry THF, 0.82 g of AIBN was added thereto, and degassed three times by freeze-pump thaw.

The resulting reaction was polymerized at 65 ° C. for about 24 hours and then precipitated in excess isopropyl alcohol solution (× 10 times). Thereafter, the precipitate was dissolved in THF again and reprecipitated in isopropyl alcohol solution. The precipitate obtained was filtered off and then dried for 24 hours in a vacuum oven maintained at 50 ° C. (Yield 80%)

At this time, the weight average molecular weight (Mw) of the obtained product was 11,000, and polydispersity (Mw / Mn) was 1.8.

Example 2

Synthesis of Copolymer

4.2 g of furanone and 5.0 g of isobutyl vinyl ether were polymerized in the same manner as in Example 1, and then purified in the same manner as in Example 1 to obtain the desired product. (Yield 85%)

At this time, the weight average molecular weight (Mw) of the obtained product was 10,100, and polydispersity (Mw / Mn) was 1.74.

Example 3

Synthesis of Terpolymer

2.52 g of furanone, 2.1 g of dihydrofuran and 9.4 g of 2-methyl-2-adamantyl methacrylate were dissolved in 12 g of THF, and then 0.82 g of AIBN was added thereto and degassed.

The resulting reaction was polymerized at 65 ° C. for about 24 hours and then precipitated in excess isopropyl alcohol solution (× 10 times). Thereafter, the precipitate was dissolved in THF again and reprecipitated in isopropyl alcohol solution. The precipitate obtained was filtered off and then dried for 24 hours in a vacuum oven maintained at 50 ° C. (73% yield)

At this time, the weight average molecular weight (Mw) of the obtained product was 8,000, and polydispersity (Mw / Mn) was 1.95.

Example 4

Synthesis of Terpolymer

2.52 g of furanone, 3.0 g of butyl vinyl ether and 9.4 g of 2-methyl-2-adamantyl methacrylate were polymerized in the same manner as in Example 3, and then purified in the same manner as in Example 3 to obtain the desired product. Got. (84% yield)

At this time, the weight average molecular weight (Mw) of the obtained product was 14,000, and polydispersity (Mw / Mn) was 1.72.

Example 5

Preparation of Resist Composition

The terpolymer (1.0 g) obtained in Example 3 was combined with triphenylsulfonium trifluoromethanesulfonate (triplate) (0.02 g) which is a PAG (photoacid generator) and triisodecylamine (2 mg) which is an organic base, After dissolving in PGMEA (propylene glycol monomethyl ether acetate) (8.0g) solution completely, using a 0.2μm membrane filter to obtain a resist composition. The resist composition was coated on an organic Anti-Reflective Coating (ARC) -treated Si wafer to a thickness of about 0.3 탆 each.

Thereafter, each wafer coated with the resist composition was soft baked for 90 seconds at a temperature of 120 ° C., exposed using an ArF excimer laser stepper (NA = 0.6), and then PEB for 90 seconds at a temperature of 120 ° C. (post exposure bake) was performed.

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

As a result, when the exposure dose amount was set to about 10 mJ / cm ² , it was confirmed that a 0.15 μm line and space pattern was obtained.

Example 6

Preparation of Resist Composition

Using the terpolymer (1.0 g) obtained in Example 4, a resist composition was obtained in the same manner as in Example 5. As a result of evaluating in the same manner as in Example 5 using this resist composition, it was confirmed that a 0.15 µm line and space pattern was obtained when the exposure dose was about 12.0 mJ / cm ² .

The photosensitive polymer according to the present invention has a basic structure including an alternating copolymer of alkyl vinyl ether and furanone having a linear or cyclic structure. Conventional photosensitive polymers containing maleic anhydride not only have unstable properties for moisture but also exhibit excessive absorbance at 193 nm, whereas the photosensitive polymer according to the present invention containing furanone instead of maleic anhydride is Problems do not occur. The resist composition according to the present invention obtained from such a photosensitive polymer not only has excellent resistance to dry etching and adhesion to the underlying film, but also has excellent storage stability and is applied to a photolithography process using a light source having a wavelength of 193 nm and 248 nm. By showing excellent high-resolution lithography performance, it can be very useful for manufacturing next-generation semiconductor devices in the future.

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 (26)

A photosensitive polymer comprising a copolymer of alkyl vinyl ether and furanone represented by the following formula. Wherein R ₁ and R ₂ are each a hydrogen atom or an alkyl group of C ₁ to C ₃ , and X is a linear or cyclic alkyl vinyl ether having any one structure selected from the structures shown below. And Of the above formulas, R ₃ is a hydrogen atom or a methyl group, R ₄ is C ₁ ~ hydrocarbon group of C _20, y is an integer of 1 ~ 4, R ₅ is a hydrogen atom, or C ₁ ~ alkyl group of C ₃ or Alkoxy group. The photosensitive polymer according to claim 1, wherein R ₄ is a methyl group, ethyl group, 2-hydroxy ethyl group, n-butyl group or iso-butyl group. The photosensitive polymer according to claim 1, wherein R ₅ is a methoxy group or an ethoxy group. (a) a copolymer of an alkyl vinyl ether and furanone represented by the following formula, Wherein R ₁ and R ₂ are each a hydrogen atom or an alkyl group of C ₁ to C ₃ , and X is a linear or cyclic alkyl vinyl ether having any one structure selected from the structures shown below. And Of the above formulas, R ₃ is a hydrogen atom or a methyl group, R ₄ is C ₁ ~ hydrocarbon group of C _20, y is an integer of 1 ~ 4, R ₅ is a hydrogen atom, or C ₁ ~ alkyl group of C ₃ or Alkoxy group. (b) comonomers having substituents or polar functional groups that can be degraded by acids The photosensitive polymer which is made by copolymerization. The photosensitive polymer according to claim 4, wherein R ₄ is a methyl group, an ethyl group, 2-hydroxy ethyl group, n-butyl group or iso-butyl group. The photosensitive polymer according to claim 4, wherein R ₅ is a methoxy group or an ethoxy group. The method of claim 4, wherein The comonomer consists of an acrylate derivative or a methacrylate derivative, The photosensitive polymer characterized by the following formula. Wherein R ₆ is a hydrogen atom or a methyl group, R ₇ is a C ₂ to C ₂₀ hydrocarbon group which can be decomposed by acid, m / (m + n) = 0.1 to 0.9, n / (m + n ) = 0.1 to 0.9. The photosensitive polymer according to claim 7, wherein R ₇ is a t-butyl group or tetrahydropyranyl group. 8. The photosensitive polymer according to claim 7, wherein R ₇ is a substituted or unsubstituted alicyclic hydrocarbon group. The compound of claim 9, wherein R ₇ is 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 8-ethyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 2-methyl-2-adamantyl, 2- A photosensitive polymer characterized by being an ethyl-2-adamantyl, 1-adamantyl-1-methylethyl, 2-methyl-2-pentyl or 2-ethyl-2-pentyl group. (a) (a-1) a copolymer of alkyl vinyl ether and furanone represented by the following formula, Wherein R ₁ and R ₂ are each a hydrogen atom or an alkyl group of C ₁ to C ₃ , and X is a linear or cyclic alkyl vinyl ether having any one structure selected from the structures shown below. And Of the above formulas, R ₃ is a hydrogen atom or a methyl group, R ₄ is C ₁ ~ hydrocarbon group of C _20, y is an integer of 1 ~ 4, R ₅ is a hydrogen atom, or C ₁ ~ alkyl group of C ₃ or Alkoxy group. (a-2) comonomers having substituents or polar functional groups that can be degraded by acids A photosensitive polymer copolymerized with (b) a resist composition comprising a photoacid generator (PAG). The resist composition of claim 11, wherein R ₄ is a methyl group, an ethyl group, 2-hydroxy ethyl group, n-butyl group or iso-butyl group. The resist composition of claim 11, wherein R ₅ is a methoxy group or an ethoxy group. The method of claim 11, The comonomer consists of an acrylate derivative or a methacrylate derivative, The photosensitive polymer is a resist composition, characterized in that the following formula. Wherein R ₆ is a hydrogen atom or a methyl group, R ₇ is a C ₂ to C ₂₀ hydrocarbon group which can be decomposed by acid, m / (m + n) = 0.1 to 0.9, n / (m + n ) = 0.1 to 0.9. The resist composition of claim 14, wherein R ₇ is a t-butyl group or a tetrahydropyranyl group. The resist composition of claim 14, wherein R ₇ is a substituted or unsubstituted alicyclic hydrocarbon group. The compound of claim 16, wherein R ₇ is 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 8-ethyl-8-tricyclo [5.2.1.0 ^2,6 ] decanyl, 2-methyl-2-adamantyl, 2- A resist composition comprising an ethyl-2-adamantyl, 1-adamantyl-1-methylethyl, 2-methyl-2-pentyl, or 2-ethyl-2-pentyl group. The resist composition according to claim 11, wherein the weight average molecular weight of the photosensitive polymer is 1,000 to 100,000. The resist composition of claim 11, wherein the PAG is included in an amount of 1 to 15 wt% based on the weight of the photosensitive polymer. 12. The resist composition of claim 11, wherein said PAG consists of triarylsulfonium salts, diaryliodonium salts, sulfonates, or mixtures thereof. The method of claim 20, wherein the PAG is triphenylsulfonium triflate, triphenylsulfonium antimonate, diphenyliodonium triflate, diphenyliodonium antiflate Monate (diphenyliodonium antimonate), methoxydiphenyliodonium triflate, di-t-butyldiphenyliodonium triflate, 2,6-dinitrobenzyl sulfonate (2,6-dinitrobenzyl sulfonates), pyrogallol tris (alkylsulfonates), N-hydroxysuccinimide triflate, norbornene-dicarboximide- Triflate (norbornene-dicarboximide-triflate), triphenylsulfonium nonaflate, diphenyliodonium nonaflate, methoxydiphenyl Methoxydiphenyliodonium nonaflate, di-t-butyldiphenyliodonium nonaflate, N-hydroxysuccinimide nonaflate, norbornene- Dicarboximide-nonaplate (norbornene-dicarboximide-nonaflate), triphenylsulfonium perfluorooctanesulfonate (PFOS), diphenyliodonium PFOS, methoxydiphenyliodonium Methoxydiphenyliodonium PFOS (PFOS), di-t-butyldiphenyliodonium triflate, N-hydroxysuccinimide PFOS (N-hydroxysuccinimide PFOS), norbornene-dicarboximide A resist composition comprising norbornene-dicarboximide PFOS (PFOS), or a mixture thereof. 12. The resist composition of claim 11, further comprising an organic base. The resist composition of claim 22, wherein the organic base is included in an amount of 0.01 to 2.0 wt% based on the weight of the photosensitive polymer. 23. The resist composition of claim 22, wherein the organic base is made of a compound consisting of tertiary amines alone or in combination of two or more thereof. The method of claim 22, wherein the organic base is triethylamine, triisobutylamine, triisooctylamine, triisodecylamine, diethanolamine, triethanolamine (triethanolamine), N-alkyl substituted pyrrolidinone, N-alkyl substituted caprolactam, N-alkyl substituted valerolactam Or a mixture thereof. The resist composition of claim 11, further comprising 30 to 200 ppm of a surfactant.