KR101036753B1 - Additive for chemically amplified photoresist composition and chemically amplified photoresist composition containing thereof - Google Patents

Abstract

The present invention relates to an additive for chemically amplified photoresist and a chemically amplified photoresist composition comprising the same. The chemically amplified photoresist additive may include a compound of Formula 1 to control diffusion of an acid component generated in an exposed part. Therefore, it is possible to suppress the diffusion of the acid component generated in the exposed portion to the non-exposed portion, thereby improving the line edge roughness and profile of the photoresist pattern.

<Formula 1>

Photoresist, additives, photoacid generators, acid diffusion

Description

Additive for chemically amplified photoresist and chemically amplified photoresist composition comprising same

The present invention relates to an additive for a chemically amplified photoresist and a chemically amplified photoresist composition comprising the same, specifically, having a weak base, and can be radicalized, thereby controlling the diffusion of an acid generated by a photoacid generator. An additive to improve line edge roughness and profile of LER and a photoresist composition comprising the same.

Recently, as the semiconductor device has been highly integrated, the necessity of forming an ultrafine pattern of 100 nm or less has been increased. For this purpose, a lithography technique using a short wavelength exposure source such as an KrF excimer laser or an ArF excimer laser has been introduced. Therefore, research has been actively conducted on photoresist compositions having not only high resolution at short wavelength exposure sources but also excellent transparency, dry etching resistance, adhesion to lower film quality, and developability.

In general, chemically amplified photoresist compositions include photoacid generators and photosensitive polymers that generate acids by exposure. The chemically amplified photoresist performs a post-exposure heating process, wherein the heated acid component penetrates into the photoresist of the non-exposed part and increases the solubility of the non-exposed part, thereby changing the line width of the photoresist pattern or causing the pattern to collapse. Line edge roughness.

Conventionally, amines or amide compounds are used as quenchers or additives in order to effectively control the acid generated by photoacid generators at the exposure sites. Excessive use of these compounds increases the light absorption and increases the optimal exposure energy. There is a disadvantage, which leads to a decrease in productivity of the exposure equipment.

In addition, the finer the pattern, the more difficult it is to control the diffusion of acid generated from the photoacid generator, so that the line edge roughness tends to increase, thereby increasing the importance of reducing the line edge roughness and decreasing the line width change due to the post-exposure heating temperature. It is becoming.

In order to solve the above problems, the present invention provides an additive for a chemically amplified photoresist and a chemically amplified photoresist composition which improves the line edge roughness and profile of the photoresist pattern by controlling the diffusion of acid generated in the photoacid generator. The purpose is to provide.

The present invention to achieve the above object,

It provides an additive for chemically amplified photoresist comprising a compound represented by the following formula (1):

<Formula 1>

(In Chemical Formula 1,

R ₁ is -OH or -SH,

R ₂ to R ₄ is an alkyl group having 1 to 10 carbon atoms,

a is 0 or 1)

The compound represented by Chemical Formula 2 may be a material of Chemical Formula 2 below:

<Formula 2>

The present invention to achieve another object of the present invention,

Additives for the chemically amplified photoresist; Photoacid generators; And it provides a chemically amplified photoresist composition comprising a photosensitive polymer.

The chemically amplified photoresist additive may be included in an amount of 0.1 to 20 mol% based on the photoacid generator.

The present invention to achieve another object of the present invention,

It provides a photoresist pattern forming method comprising applying a chemically amplified photoresist composition of the present invention to the upper surface of the etched film to form a photoresist layer.

In the case of using the photoresist composition including the additive of the present invention, the diffusion of acid generated by the photoacid generator is effectively controlled to reduce the line edge roughness and improve the profile when forming the photoresist pattern.

Therefore, the line width of the pattern can be kept constant in a process requiring a fine pattern, and the desired uniform pattern can be obtained by reducing the collapse of the pattern.

Hereinafter, the present invention will be described in detail.

The chemically amplified photoresist additive of the present invention includes a compound represented by the following Chemical Formula 1:

<Formula 1>

(In Chemical Formula 1,

R ₁ is -OH or -SH,

R ₂ to R ₄ is an alkyl group having 1 to 10 carbon atoms,

a is 0 or 1)

The amine group included in the compound represented by Formula 1 has a weak basicity as a tertiary amine. Therefore, the diffusion of the acid generated in the exposed portion can be adjusted without completely absorbing the acid generated by the photoacid generator.

As a compound represented by Chemical Formula 1, a material of Chemical Formula 2 may be used:

<Formula 2>

When the photoresist composition is exposed, an acid component is generated from the photoacid generator, and the resulting acid component is serially decomposed to a protecting group bound to the skeleton of the polymer resin, thereby changing the solubility of the polymer resin, thereby resulting in high contrast. To form a pattern having.

In order to activate and diffuse the acid component present in the exposed photoresist composition, a post exposure baking (PEB) process is performed. The compound represented by Chemical Formula 2 in the exposed part is heat An acid catalyst forms radicals such as the following Chemical Formulas 3 to 5 below.

<Formula 3>

<Formula 4>

<Formula 5>

In the exposed portion, the radicals of Chemical Formulas 3 to 5 effectively adjust the diffusion rate and distance of the acid by repeating a mechanism of combining with the acid generated by the photoacid generator and releasing the acid again. Therefore, the acid generated in the exposed portion prevents penetration into the non-exposed portion, thereby preventing the solubility of the non-exposed portion from increasing due to the penetration of the acid generated in the exposed portion.

Chemically amplified photoresist composition of the present invention is an additive for the chemically amplified photoresist; Photoacid generators; And photosensitive polymers.

Since the chemically amplified photoresist composition of the present invention includes an additive including the compound of Chemical Formula 1, it is possible to control diffusion of an acid generated by a photoacid generator, thereby obtaining a uniform pattern having improved line edge roughness. .

The additive including the compound of Formula 1 may be included in 0.1 to 20 mol% with respect to the photoacid generator, preferably 1 to 15 mol%.

If it is added less than 0.1 mol%, the effect of controlling the diffusion of acid is insignificant, so that acid generated in the exposed portion penetrates into the non-exposed portion, so that the solubility of the non-exposed portion increases, causing line edge roughness, etc. The degree of disturbance of acid diffusion is so strong that the solubility of the photoresist in the exposed part is reduced during the development process, making it difficult to realize a desired shape pattern.

The photoacid generator generates an acid component such as H ⁺ by exposure to induce a chemical amplification action, and those commonly known in the art may be used without limitation. Specific examples of the photoacid generator include phthalimidotrifluoromethanesulfonate, dinitrobenzyltosylate, n-decyldisulfone, and naphthyl imido, having low absorbance at 157 nm and 193 nm. Trifluoromethanesulfonate, naphthylimidotrifluoromethanesulfonate, diphenylyldono hexafluorophosphate, diphenyliodonium hexafluoroarsenate, diphenyliodonium hexafluoroarsenate, diphenyliodon hexafluoroantimonate, diphenyliodonium hexafluoroantimonate Toluenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium triflate, dibutylnaphthylsulfonium triflate A mixture thereof may be used.

The photoacid generator may be included in an amount of 0.05 to 20 parts by weight based on 100 parts by weight of the photosensitive polymer. If the amount is less than 0.05 parts by weight, the sensitivity of the photoresist composition to light is reduced, which may make deprotection of the protecting group difficult. If it is added in excess of 20 parts by weight, a large amount of acid may be generated, resulting in poor cross section of the photoresist pattern. have.

The photosensitive polymer may be used without limitation to those known in the art, and more specifically, a photosensitive polymer including a repeating unit represented by Chemical Formula 6 may be used.

<Formula 6>

(In Chemical Formula 6,

R ₆ is an alkyl or cycloalkyl group having 1 to 30 carbon atoms unsubstituted or substituted with hydrogen or fluorine.)

R ₅ of the repeating unit is an acid-sensitive protecting group, and R ₅ may be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a cycloalkyl group, with or without an ester group or ester group. Specific examples of the R ₅ , t-butyl, tetrahydropyran-2-yl, 2-methyl tetrahydropyran-2-yl, tetrahydrofuran-2-yl, 2-methyl tetrahydrofuran-2-yl, 1-methoxypropyl, 1-methoxyl-1-methylethyl, 1-ethoxypropyl, 1-ethoxy-1-methylethyl, 1-methoxyethyl, 1-ethoxyethyl, t-butoxyethyl, 1-isobutoxyethyl or 2-acetylment-1-yl, adamantyl and the like.

In addition to the repeating unit represented by Chemical Formula 6, the photosensitive polymer may further include a cycloolefin repeating unit, a repeating unit or crosslinkable repeating unit commonly used in the preparation of the photosensitive polymer.

The photosensitive polymer may be a block copolymer or a random copolymer, and a weight average molecular weight (Mw) of 3,000 to 100,000 may be used. As a specific example of the photosensitive polymer may be used a photosensitive polymer represented by the following formula (7):

<Formula 7>

(In Chemical Formula 7,

R ₇ is hydrogen, methyl or ethyl

R ₈ to R ₁₀ is an alkyl or cycloalkyl group having 1 to 30 carbon atoms unsubstituted or substituted with hydrogen or a fluorine group,

x, y and z are mole% with respect to the total repeating units, 1 to 60 mole% respectively.)

In order to form a uniform and flat photoresist layer, the photoresist composition is used by dissolving in the organic solvent having an appropriate evaporation rate and viscosity.

The organic solvent may be used without limitation, those known in the art, specifically, ethylene glycol monomethyl ethyl, ethylene glycol monomethyl ether, ethylene glycol mono ethyl ether, ethylene glycol monoacetate, diethylene glycol, diethylene glycol Monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol, propylene glycol monoacetate, toluene, xylene, methyl ethyl ketone, methyl isoamyl ketone, cyclohexaone, dioxane, methyl lactate, ethyl lactate, methyl Pyruvate, ethylpyruvate, methylmethoxypropionate, ethylethoxypropionate, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 3-e Methoxyethylpropionate, 2-heptaone, gamma-butyrolactone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy 2-methylpropionate, ethoxyacetic acid Methyl, ethyl hydroxy acetate, 2-hydroxy methyl methyl butyrate, 3-methoxy methyl 2-methylpropioate, ethyl 3-ethoxypropionate, ethyl 3-methoxy-2-methylpropionate, ethyl acetate, Butyl acetate and mixtures thereof can be used.

The photoresist composition may further include an organic base as necessary. The organic base may be used without limitation those known in the art, specifically triethylamine, triethylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine and mixtures thereof may be used. have.

The organic base may be included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the photoresist composition. If it is included in less than 0.01 parts by weight, a t-top phenomenon may occur in the photoresist pattern, and if it is included in excess of 10 parts by weight, the sensitivity of the photoresist composition may be lowered, thereby decreasing the pattern formation rate.

The method of forming a photoresist pattern of the present invention includes applying the photoresist composition of the present invention to an upper surface of an etched film to form a photoresist layer.

By forming a photoresist layer including an additive including the compound of Formula 1 on the upper surface of the etched film, the diffusion of acid generated by the photoacid generator in the exposed portion is controlled, and the non-exposed portion absorbs the acid that has penetrated from the exposed portion. Therefore, the occurrence of line edge roughness can be suppressed and a pattern having a uniform shape can be formed.

The photoresist composition of the present invention is applied to a top surface of an etching target film such as a silicon wafer or an aluminum substrate by using a spin coater or the like to form a photoresist layer. The photoresist pattern is formed by a conventional lithography process, such as an exposure process of exposing the photoresist layer in a predetermined pattern, a post exposure baking (PEB) process, and a developing process. The exposure process may use not only ArF but also KrF, F2, Extreme Ultra Violet (EUV), Vacuum Ultra Violet (VUV), E-beam, X-ray, Immersion lithography or ion beam, and 1 to 100 mJ / It is preferable to carry out with an exposure energy of cm ² . As a developing solution used in the developing step, an alkaline aqueous solution in which alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate and tetramethylammonium hydroxide (TMAH) are dissolved at a concentration of 0.1 to 10% by weight may be used. Accordingly, an appropriate amount of a water-soluble organic solvent such as methanol and ethanol and a surfactant may be added to the developer. In addition, after performing such a developing process, a cleaning process of cleaning the substrate with ultrapure water may be performed.

Hereinafter, the present invention will be described in detail through examples. This is only one embodiment of the present invention is not limited thereby.

&Lt; Example 1 >

1-1. Preparation of Photosensitive Polymer

2-methyl-2-adamantyl-5-norbonene-2-carboxylate (0.161mol), maleic anhydride (0.161mole), 2-methyl-2-adamantyl-methacrylate (0.05mole) and 10g of AIBN (azobisisobutylronitrile) as an initiator The solution was dissolved in 100 g of THF, degassed using an ampoule as a freezing method, and then polymerized at 66 ° C. for 24 hours. The polymerization product was reprecipitated in an excess of diethyl ether to obtain a photosensitive polymer resin.

1-2. Preparation of Photoresist Composition

2.0 g of the photosensitive polymer resin and 0.02 g of triphenyl sulfonium triflate (TPS-105) obtained in Example 1-1 were completely dissolved in 20 g of propylene glycol monomethyl ether acetate (PGMEA). It added in the quantity of 5 mol% with respect to the triphenyl sulfonium triflate which is a generator, and filtered with the 0.2 micrometer disk filter to obtain the photoresist composition.

<Example 2>

A photoresist composition was prepared in the same manner as in Example 1-2, except that the compound of Formula 2 was added in an amount of 10 mol% based on triphenyl sulfonium triflate.

<Example 3>

A photoresist composition was prepared in the same manner as in Example 1-2, except that the compound of Formula 2 was added in an amount of 15 mol% based on triphenyl sulfonium triflate.

Comparative Example 1

A photoresist composition was obtained in the same manner as in Example 1-2, except that the compound of Formula 2 was not included.

Comparative Example 2

A photoresist composition was prepared in the same manner as in Example 1-2, except that the compound of Formula 2 was added in an amount of 30 mol% with respect to triphenyl sulfonium triflate.

Experimental Example 1

The photoresist compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were coated on a silicon wafer treated with hexamethyldisilazane (HMDS) to a thickness of about 0.2 μm to form a photoresist layer. The wafer on which the photoresist layer was formed was prebaked at 100 ° C. for 90 seconds, exposed using a ArF excimer laser having a numerical aperture of 0.60 in a predetermined pattern, and then subjected to PEB at 100 ° C. for 90 seconds. And it developed for 30 second by TMAH solution, and obtained the same line and space pattern of 0.1 micrometer.

The results of measuring the line etch roughness of the photoresist pattern formed in the above experimental example are shown in Table 1 and the results of observing the shape of the pattern by electron microscope are shown in FIGS. 1 to 6.

 LER (nm) Example 1 3.6 Example 2 2.8 Example 3 2.7 Comparative Example 1 5.6 Comparative Example 2 4.1

As shown in Table 1, it can be seen that in Examples 1 to 3 including Formula 2, the line edge roughness is improved compared to the comparative example.

1 to 6, it can be seen that when the photoresist composition of the example is used, a pattern having improved line edge roughness and a profile is formed, and in the case of Comparative Example 1 that does not include the additive of the present invention of Formula 2, Edge roughness increased and no uniform pattern was formed. In Comparative Example 2 containing a lot of additives of the formula (2) it is confirmed that the degree of inhibiting the diffusion of the acid is so severe that the photoresist remains as a defect in the exposed portion after development.

1 is a result of observing a photoresist pattern formed using the photoresist composition of Example 1 with an electron microscope.

2 is a result of observing a photoresist pattern formed using the photoresist composition of Example 2 with an electron microscope.

3 is a result of observing a photoresist pattern formed using the photoresist composition of Example 3 with an electron microscope.

4 is a result of observing a photoresist pattern formed using the photoresist composition of Comparative Example 1 with an electron microscope.

5 is a result of observing a photoresist pattern formed using the photoresist composition of Comparative Example 2 with an electron microscope.

Claims (5)

An additive for chemically amplified photoresist comprising a compound represented by the following Chemical Formula 1: <Formula 1>

(In Chemical Formula 1, R ₁ is -OH or -SH, R ₂ to R ₄ is an alkyl group having 1 to 10 carbon atoms, a is 0 or 1) The method of claim 1, An additive for chemically amplified photoresist, characterized in that the compound represented by Formula 1 is a substance of the following Formula 2: <Formula 2>

The additive for chemically amplified photoresist of claim 1; Photoacid generators; And a chemically amplified photoresist composition comprising a photosensitive polymer. The method of claim 3, The chemically amplified photoresist composition is a chemically amplified photoresist composition, characterized in that contained in 0.1 to 20 mol% based on the photoacid generator. A method of forming a photoresist pattern comprising applying a chemically amplified photoresist composition of claim 3 or 4 to an upper surface of a etched film to form a photoresist layer.

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