KR101416038B1 - Salt for controlling acid-diffusion and photoresist composition including the same - Google Patents

Abstract

Disclosed is an acid-diffusion controlling salt and a photoresist composition containing the same, which can control diffusion of an acid generated in an exposed portion of a photolithography process. The basic compound has a structure represented by the following formula.

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, R - represents anion of strong acid.

Photoresist, acid diffusion, salt compound, resolution

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acid-diffusion-controlling salt and a photoresist composition containing the same,

The present invention relates to a salt for acid-diffusion control and a photoresist composition containing the same, and more particularly, to a salt for acid-diffusion control, which can control the diffusion of an acid generated in an exposed portion of a photolithography process, And a photoresist composition comprising the same.

In order to process a semiconductor wafer or a glass for display to manufacture a semiconductor chip or a display device, a circuit structure of a predetermined pattern must be formed using a photolithography process. The photosensitive material used in the photolithography process is referred to as a photoresist composition. Recently, as the circuit pattern of a semiconductor or a display device has become finer, a photoresist composition having a high resolution has been demanded.

Conventional chemically amplified photoresist compositions include photoresist polymers, photoacid generators (PAGs), organic solvents, and basic compounds. In such a chemically amplified photoresist, when light of a predetermined pattern from the exposure source is irradiated to the photoresist composition, an acid component is generated in the exposed photo acid generator, and the protecting group bonded to the photoresist polymer by the generated acid The solubility of the photoresist polymer is changed. Thus, when the solubility of the photoresist film is changed according to the exposure pattern, and then the photoresist film is developed, a desired photoresist pattern can be formed. In such a photolithography process, a post exposure bake (PEB) process is typically performed to activate and diffuse the acid component present in the exposed photoresist. Further, in order to control diffusion of the acid component, a basic compound is added to the photoresist composition.

In addition, since a fine photoresist pattern having a line width of 60 nm or less is required to be formed, the wall roughness and line edge roughness (LER) of the photoresist pattern are reduced and the contrast of the exposed and non- there have been various studies to improve the contrast. In order to improve the contrast between the exposed portion and the unexposed portion boundary, a smooth interaction between the photoresist polymer, the photoacid generator, and the basic compound must be performed. Therefore, these actions are effectively assisted to improve the contrast between the exposed portion and non- And the like.

It is an object of the present invention to provide an acid-diffusion controlling salt (Salt) capable of controlling diffusion of an acid generated in an exposed portion of a photolithography process, and a photoresist composition containing the same.

Another object of the present invention is to provide an acid-diffusion control salt and a photoresist composition containing the same, which can improve the contrast at the interface between the exposed portion and the non-exposed portion and improve the side wall roughness and line edge roughness of the photoresist pattern .

In order to achieve the above object, the present invention provides, as one of components constituting the photoresist composition, an acid-diffusion controlling salt represented by the following general formula (1).

 [Chemical Formula 1]

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, R ^- represents an anion of strong acid.

The present invention also relates to a photoresist composition comprising 0.01 to 10% by weight of an acid-diffusion controlling salt represented by the above formula (1); 0.05 to 20 parts by weight of a photoacid generator based on 100 parts by weight of the photosensitive compound; And a remaining organic solvent. The present invention also provides a method of manufacturing a semiconductor device, comprising: a) forming a photoresist film by applying the photoresist composition on a substrate; b) exposing the photoresist film to a predetermined pattern; And c) post-exposure heating the exposed photoresist film; And d) developing the heated photoresist film to obtain a pattern.

The acid-diffusion controlling salt according to the present invention can effectively control the diffusion of acid generated in the exposed portion of the photolithography process to improve the contrast at the interface between the exposed portion and the non-exposed portion, The edge roughness can be improved. Further, the acid-diffusion controlling salt according to the present invention has the effect of increasing the activation of the acid in an area where the acid distribution is small and uniformly distributing the acid as a whole.

Hereinafter, the present invention will be described in detail.

The acid-diffusion controlling salt according to the present invention is a salt in which an anion and a base are combined with each other, and is represented by the following general formula (1).

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, An alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and R ^- represents an anion generated in the photoacid generator.

,

,

,

,

,

,

,

,

,

등을 예시할 수 있다.If necessary, R ₁ , R ₂ and / or R ₃ may be connected to each other to form a mono-cyclic or multi-cyclic ring structure, preferably R ₂ and R ₃ may be connected to each other to form a piperidine structure, or R ₂ and R ₁ may be connected to each other to form a piperidine structure, and R ^- is an anion generated in a photoacid generator And more preferably,

,

,

,

,

,

,

,

,

,

And the like.

Representative examples of the acid-diffusion controlling salt compound represented by the above-mentioned formula (1) are as follows.

(화학식 2a),

(화학식 2b),

(Formula 2a),

(Formula 2b),

(화학식 2c),

(화학식 2d),

(Formula 2c),

(Formula 2d),

(화학식 2e),

(화학식 2f),

(Formula 2e),

(2f),

(화학식 2g),

(화학식 2h),

(Formula 2g),

(2h),

(화학식 2i),

(화학식 2j),

(2i),

(2j),

(화학식 2k),

(화학식 2l)

(Formula 2k),

(Formula 21)

The acid-diffusion controlling salt according to the present invention is a salt in which an anion and a base are combined in a photoacid generator and has both an acid and a base. Thus, the acid- Can be adjusted.

The acid-diffusion controlling salt according to the present invention can be prepared by various conventional organic synthesis methods. For example, as shown in the following Reaction Schemes 1 to 3, when the basic compound and the anion material of the photo-acid generator are mixed in an aqueous solution at room temperature, the acid-base diffusion reaction salt of the present invention . The salt thus formed is purified several times with an organic solvent such as ethyl acetate (EA) and dried to obtain a solid acid-diffusion controlling salt.

The photoresist composition according to the present invention comprises a photosensitive compound which reacts with an acid-diffusion controlling salt represented by the above-mentioned formula (1) and an acid to change its solubility in a developer, a photoacid generator and an organic solvent, as a quencher, a basic compound, a surfactant, and the like. In the photoresist composition according to the present invention, the acid-diffusion controlling salt represented by Formula 1 is used in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 To 3% by weight. If the content of the acid-diffusion controlling salt represented by the above formula (1) is too small, there is a fear that the resolution of the photoresist pattern and the improvement in the lager edge roughness may not be sufficient. If the content of the basic compound is too large, There is a fear that the photoresist pattern is deformed or a defect is generated in the photoresist pattern.

In the photoresist composition of the present invention, as the photosensitive compound, a conventional photoresist polymer, a photosensitive monomolecular compound, etc., which reacts with an acid to change the solubility in a developing solution, may be used without limitation. The photoresist polymer may be a block copolymer or a random copolymer having an acid-sensitive protecting group, and preferably has a weight average molecular weight (Mw) of 3,000 to 20,000. The content of the photosensitive compound is preferably 1 to 30% by weight, more preferably 1 to 20% by weight, based on the entire photoresist composition. If the content of the photoresist polymer is less than 1% by weight, the resist layer remaining after coating is too thin to form a desired thickness pattern, and if it exceeds 30% by weight, coating uniformity may be lowered.

The photoacid generator is capable of generating an acid by exposure to deprotect the protecting group of the photoresist polymer or to convert the structure of the basic compound, And any of them can be used. Preferably, a sulfur-based compound such as an organic sulfonic acid or an onium salt-based compound such as an onium salt may be used alone or in combination. Non-limiting examples of the photoacid generator include phthalimidotrifluoromethane sulfonate, dinitrobenzyl tosylate, n-decyl disulfone, naphthylimidotrifluoro Naphthylimido trifluoromethane sulfonate, diphenyl iodide salt hexafluorophosphate, diphenyl iodide salt hexafluoroarsenate, diphenyl iodide salt hexafluoroantimonate, diphenyl para methoxy phenyl sulfonium triflate, di Phenyl paratoluenesulfonium triflate, diphenyl paraisobutyl phenyl sulfonium triflate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium triflate, di Butylnaphthylsulfonium triflate, triphenylsulfonium nonaplate, mixtures thereof, and the like. The content of the photoacid generator is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the photosensitive compound. If the content of the photoacid generator is less than 0.05 parts by weight, the sensitivity of the photoresist composition to light may be lowered, which may result in difficulty in deprotonating the protective group or converting the structure of the basic compound. If the content of the photoacid generator is more than 20 parts by weight, There is a possibility that a large amount of acid is generated in the resist pattern, resulting in a poor cross-sectional shape of the resist pattern.

As the organic solvent constituting the remaining components of the photoresist composition according to the present invention, various organic solvents commonly used in the production of the photoresist composition can be widely used. Specific examples thereof include ethylene glycol monomethylethyl, ethylene Propylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol, propylene glycol monoacetate, toluene, xylene, Methyl ethyl ketone, methyl isoamyl ketone, cyclohexanone, dioxane, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxy propionate, ethyl ethoxy propionate, N, N -Dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 3- Hydroxypropionate, ethyl 2-hydroxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-hydroxypropionate, Methyl 3-methoxypropionate, ethyl 3-methoxy-2-methylpropionate, ethyl acetate, butyl acetate, and mixtures thereof. The content of the organic solvent is preferably 300 to 5000 parts by weight based on 100 parts by weight of the entire photosensitive compound. If the content of the organic solvent is out of the above range, the photoresist film forming process may not be performed smoothly.

Also, in order to control acid diffusion, when conventional basic compounds are used, there may be used triethylamine, trioctylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine Amines, mixtures thereof, and the like can be used. The amount of the basic compound to be used is preferably 0.01 to 10% by weight based on the total photoresist composition. The surfactant optionally contained in the photoresist composition according to the present invention is added for the purpose of improving the homogeneous mixing property of the photoresist composition components, the applicability of the photoresist composition, and the post-exposure developability of the photoresist composition. As such a surfactant, a conventional surfactant used in a photoresist composition may be used without limitation. For example, a fluorine-based surfactant, a fluorine-silicon-based surfactant, and the like may be used. The amount of the surfactant to be used is 0.001 to 2 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the solid content of the photoresist composition. When the amount of the surfactant is too small, , And if it is too large, the resist properties other than the coating properties such as shape stability and storage stability of the composition may be adversely affected.

In order to form a photoresist pattern using the photoresist composition of the present invention, (a) first, a photoresist composition is applied onto a substrate such as a silicon wafer or an aluminum substrate using a spin coater or the like, (B) exposing the photoresist film to a predetermined pattern, (c) post exposure bake (PEB) the exposed photoresist film, (d) developing the heated photoresist film to form a pattern Is performed by a conventional photolithography process. The exposure process may be carried out by using any one of ArF (193 nm), KrF (248 nm), F ₂ (157 nm), EUV (Extreme Ultra Violet, 13.5 nm), VUV (Vacuum Ultra Violet) Lithography (Immersion lithography) or ion beam. The developing solution used in the developing step may be an aqueous alkaline solution prepared by dissolving an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, tetramethylammonium hydroxide (TMAH) in a concentration of 0.1 to 10 wt% , An appropriate amount of a water-soluble organic solvent such as methanol, ethanol, etc. and a surfactant may be added to the developer. Further, after such a developing step, a cleaning step of cleaning the substrate with ultrapure water may be further performed.

Hereinafter, the present invention will be described in more detail by way of specific examples and comparative examples. The following examples are intended to further illustrate the present invention and are not intended to limit the scope of the present invention.

[Examples 1-1 to 1-12] Synthesis of acid-diffusion controlling salt

The basic compound and the acid substance (anion substance) constituting the acid-diffusion-controlling salt represented by the general formulas (2a) to (2l) are respectively made into an aqueous solution having a concentration of 30% by weight and then the basic compound and the acid substance are reacted After mixing and stirring for 2 hours, a salt substance dissolved in water was obtained through a heating process. After completion of the reaction, the reaction solution was vacuum-dried to remove water, and a solid salt was obtained. A solid salt was obtained in an amount of 7 times (by weight) ethyl acetate (EA) Dissolved, filtered with filter paper to remove impurities, and then vacuum dried again to give a purified solid form of the salt. This purification process was repeated three times. The amounts and yields of raw materials used in the preparation of acid-diffusion controlling salts are shown in Table 1 below.

Example salt substance Basic compound Acid material yield Kinds Input (g) Kinds Input (g) Weight (g) % One Formula 2a Formula 3a 18.32 4a 42.9 19.4 31.7% 2 2b Formula 3a 18.32 4b 58.9 25.4 32.9% 3 Formula 2c Formula 3a 18.32 Formula 4c 41.9 22.1 36.7% 4 2d Formula 3a 18.32 4d 83.0 35.4 34.9% 5 2e 3b 18.31 4a 42.9 20.4 33.3% 6 2f 3b 18.31 4b 58.9 28.2 36.5% 7 2g 3b 18.31 Formula 4c 41.9 22.1 36.7% 8 2h 3b 18.31 4d 83.0 38.4 37.9% 9 2i Formula 3c 18.31 4a 42.9 20.4 33.3% 10 2j Formula 3c 18.31 4b 58.9 30.1 39.0% 11 2k Formula 3c 18.31 Formula 4c 41.9 25.4 42.2% 12 2l Formula 3c 18.31 4d 83.0 36.2 35.7%

(분자량: 128.22), 화학식 3b는

(분자량: 128.17), 화학식 3c는

(분자량: 128.17), 화학식 4a는

(분자량: 300.1), 화학식 4b는

(분자량: 412.23), 화학식 4c는

(분자량: 293.16), 화학식 4d는

(분자량: 412.23)를 나타낸다.In the above Table 1,

(Molecular weight: 128.22), the formula (3b)

(Molecular weight: 128.17), the formula (3c)

(Molecular weight: 128.17), the formula (4a)

(Molecular weight: 300.1), the formula (4b)

(Molecular weight: 412.23), the formula (4c)

(Molecular weight: 293.16), the formula (4d)

(Molecular weight: 412.23).

[Examples 2-1 to 2-12, Comparative Example 1] Photoresist composition production and pattern formation

10% by weight of a photoresist polymer (a / b / c = 40/40/20, unit: mol%) represented by the following Chemical Formula 5 was added to the acid diffusion controlling salt to confirm the effect of improving the line edge roughness (LER) 3.5 parts by weight of triphenylsulfonium nonanaflate (TPS-NF) was added to 100 parts by weight of the polymer, 0.2% by weight of trioctylamine (TOA) as a basic compound and propylene glycol monomethyl ether acetate (PGMEA) , A photoresist composition was prepared. To the 100 parts by weight of the polymer, 0.5 parts by weight and 1 part by weight of the acid-diffusion controlling salt prepared in Examples 1-1 to 1-12 were added. The resulting photoresist composition was coated on the substrate to a thickness of 2700 ANGSTROM, and a 1: 1 line / space (L / S) pattern having a line width of 90 nm was formed using ASML 1100 equipment (0.75 NA) 120 ° C / 60 seconds). At this time, the LER value was measured using a Hitachi SEM (S8820). The results are shown in Table 2 (Examples 2-1 to 2-12). Further, the same experiment was carried out without adding the acid-diffusion controlling salt, and the LER value was measured. The results are also shown in Table 2 (Comparative Example 1).

Acid-diffusion control salt Amount used (parts by weight) LER Value (nm) Pattern shape Comparative Example 1 none none 9.8 right angle Example 2-1 Formula 2a 0.5 5.4 right angle Example 2-1 Formula 2a One 4.3 right angle Example 2-2 2b 0.5 6.2 right angle Example 2-2 2b One 5.8 right angle Example 2-3 Formula 2c 0.5 6.6 right angle Example 2-3 Formula 2c One 6.0 right angle Examples 2-4 2d 0.5 6.4 right angle Examples 2-4 2d One 6.1 right angle Example 2-5 2e 0.5 5.0 right angle Example 2-5 2e One 4.2 right angle Examples 2-6 2f 0.5 6.2 right angle Examples 2-6 2f One 5.9 right angle Examples 2-7 2g 0.5 6.7 right angle Examples 2-7 2g One 5.9 right angle Examples 2-8 2h 0.5 6.6 right angle Examples 2-8 2h One 6.0 right angle Examples 2-9 2i 0.5 4.5 right angle Examples 2-9 2i One 4.0 right angle Examples 2-10 2j 0.5 5.8 right angle Examples 2-10 2j One 5.2 right angle Examples 2-11 2k 0.5 6.0 right angle Examples 2-11 2k One 5.7 right angle Examples 2-12 2l 0.5 6.2 right angle Examples 2-12 2l One 5.4 right angle

From Table 2, it can be seen that when the acid-diffusion controlling salt according to the present invention is used, the LER can be effectively improved and the shape of the pattern is formed into a rectangle.

Claims (6)

An acid-diffusion controlling salt represented by the following general formula (1) as one component constituting the photoresist composition.  [Chemical Formula 1]

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 10 carbon atoms , And R ^- represents an anion generated in the photoacid generator. The acid-diffusion controlling salt according to claim 1, wherein R ₁ , R ₂ and / or R ₃ are connected to each other to form a monocyclic or polycyclic ring structure. The acid-diffusion controlling salt according to claim 1, wherein R ₂ and R ₃ or R ₁ are connected to each other to form a piperidine structure. 2. The method of claim 1, wherein the acid-

(Formula 2a),

(Formula 2b),

(Formula 2c),

(Formula 2d),

(Formula 2e),

(2f),

(Formula 2g),

(2h),

(2i),

(2j),

(2k), and

Lt; RTI ID = 0.0 > (II). ≪ / RTI > 0.01 to 10% by weight, based on the entire photoresist composition, of an acid-diffusion controlling salt represented by the following formula (1) [Chemical Formula 1]

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 10 carbon atoms , R- represents an anion generated in the photoacid generator; 1 to 30% by weight, based on the entire photoresist composition, of a photosensitive compound; 0.05 to 20 parts by weight of a photoacid generator based on 100 parts by weight of the photosensitive compound; And And the remaining organic solvent. A photoresist composition, comprising: a) 0.01 to 10% by weight of an acid-diffusion controlling salt represented by the following formula (1), reacted with an acid to change the solubility in a developing solution to 1 to 30% compound; 0.05 to 20 parts by weight of a photoacid generator based on 100 parts by weight of the photosensitive compound; And a remaining organic solvent on a substrate to form a photoresist film, [Chemical Formula 1]

Wherein R ₁ is a carbonyl group (-CO-) or an alkyl group or an alkylcarbonyl group having 1 to 10 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 10 carbon atoms , R- represents an anion generated in the photoacid generator; b) exposing the photoresist film to a predetermined pattern; And c) post-exposure heating the exposed photoresist film; And d) developing the heated photoresist film to obtain a pattern.