An additive for arf immersion photoresist and a photoresist containing the same

Abstract

The application discloses an additive for 193nm wet photoresist, a preparation method and application thereof. The photoresist comprises the following raw materials: an additive shown as formula I, a resin shown as formula (L), a photoacid generator and a solvent, wherein the weight average molecular weight of the additive is 1000-3000; and the weight average molecular weight / number average molecular weight ratio of the additive is 1-5. The photoresist can improve the problem that the material is immersed in water during the immersion lithography exposure process, so that a photoresist film micro-pattern with excellent sensitivity and high resolution can be formed.

Description

TECHNICAL FIELD

[0001] The present application relates to an additive for ArF immersion photoresist and a photoresist containing the same. BACKGROUND

[0002] With the higher integration and higher speed of large scale integrated circuits (LSI) in recent years, accurate micro patterning of photoresist is required. As an exposure light source used in forming a resist pattern, an ArF light source (193 nm) or a KrF light source (248 nm) has been widely used.

[0003] In ArF immersion photolithography using an ArF excimer laser as a light source, the space between a projection lens and a wafer substrate is filled with water. According to this method, even if a lens having an NA of 1.0 or more is used, the refractive index of water at 193 nm can be utilized to form a pattern, and this method is generally referred to as immersion photolithography. However, since the photoresist film is directly in contact with water, the photoresist pattern can be deformed or can collapse due to swelling, or various defects such as bubbles and watermarks can occur. For this reason, there is an urgent need to develop a photoresist resin or an additive that can improve this situation. SUMMARY

[0004] In view of the above problems in the prior art, the present application aims to provide an additive for ArF immersion photoresist and a photoresist containing the same, and the photoresist of the present application can improve the problem of material being immersed in water during immersion photolithography exposure, so that a photoresist film micro pattern with excellent sensitivity and high resolution can be formed.

[0005] The present application also provides a photoresist comprising the following raw materials: an additive as shown in Formula I, a resin as shown in Formula (L), a photoacid generator, and a solvent; the weight average molecular weight of the additive is 1000-3000, preferably 1500-2500 (for example, 1940); the weight average molecular weight / number average molecular weight ratio of the additive is 1-5, preferably 1-2 (for example, 1.1);

[0006]

[0007] The additive as shown in Formula I is:

[0008]

[0009] In a certain aspect, the preparation method of the additive comprises the following steps:

[0010] S1: In an organic solvent, compound B1 is subjected to an acetal reaction with L-tartaric acid dimethyl ester and p-toluene sulfonic acid to obtain compound C1 (2,3-bicyclo[2,2,1]hept-5-en-2-one-L-tartaric acid diethyl ester); the compound B1 is

[0011] S2: in a solvent, under the action of a base, the compound C1 is subjected to ester hydrolysis reaction to prepare compound D1 (2,3-bicyclo[2,2,1]hept-5-en-2-one-L-tartaric acid);

[0012] S3: in an organic solvent, the compound D1 is subjected to polymerization reaction with 4-dimethylaminopyridine to prepare the additive as shown in formula I.

[0013] In S1, the organic solvent can be a conventional organic solvent for such reaction in the art, preferably an aromatic hydrocarbon solvent, such as toluene.

[0014] In S1, the molar ratio of the compound B1 to the L-tartaric acid dimethyl ester can be conventional for such reaction in the art, preferably 1:(1-1.5), such as 1:1.

[0015] In S1, the molar ratio of the compound B1 to the p-toluenesulfonic acid can be conventional for such reaction in the art, preferably 1:(20-60), such as 1:38.5.

[0016] In S1, the post-treatment step of the acetal reaction can be a conventional post-treatment step in the art, preferably including washing, drying, filtering and removing solvent. The washing solvent can be conventional for such reaction in the art, preferably washing with sodium bicarbonate aqueous solution, water and brine in sequence. The drying is preferably magnesium sulfate drying.

[0017] In S1, the reaction time of the acetal reaction is subject to the reaction of the reactants being complete, preferably 26 hours to 60 hours, such as 48 hours.

[0018] In S1, the temperature of the acetal reaction is preferably the refluxing temperature of the solvent at normal temperature and pressure of the solvent.

[0019] In S2, the solvent can be a conventional solvent for such reaction in the art, preferably a ketone solvent, such as N-methylpyrrolidone.

[0020] In S2, the base can be a conventional base for such reaction in the art, preferably an inorganic base, such as potassium hydroxide and / or sodium hydroxide, preferably potassium hydroxide.

[0021] In S2, the molar volume ratio of the compound C1 to the solvent can be conventional for such reaction in the art, preferably 0.1-0.7 mol / L, such as 0.5 mol / L.

[0022] In S2, the base preferably participates in the reaction in the form of an aqueous base. The mass ratio of the base to water is preferably 0.1:1-0.6:1, such as 0.3:1.

[0023] In S2, the ester hydrolysis reaction can further comprise a post-treatment step after the reaction is completed. The post-treatment step can be conventional for such reactions in the art, for example, comprising neutralization and purification. The purification step is preferably carried out by chromatography, and more preferably, ethyl acetate is used as the eluent in the chromatography.

[0024] In S2, the time for the ester hydrolysis reaction is determined by the time when the reaction no longer proceeds, and is preferably 3-15 hours, for example, 6 hours.

[0025] In S2, the temperature for the ester hydrolysis reaction is preferably the reflux temperature of the solvent at normal temperature and pressure.

[0026] In S3, the organic solvent can be any organic solvent commonly used in such reactions in the art, and is preferably an acid anhydride, for example, acetic anhydride.

[0027] In S3, the molar ratio of 4-dimethylaminopyridine to compound Dl can be conventional for such reactions in the art, and is preferably 0.0006-0.0012:1, for example, 0.001:1.

[0028] In S3, the molar ratio of the organic solvent to compound Dl can be conventional for such reactions in the art, and is preferably 3:1-7:1, for example, 5:1.

[0029] In S3, the time for the polymerization reaction is determined by the time when the reaction no longer proceeds, and is preferably 3-15 hours, for example, 6-10 hours.

[0030] In S3, the temperature for the polymerization reaction can be conventional for such reactions in the art, and is preferably 100-200°C, for example, 130-190°C.

[0031] In S3, the polymerization reaction is preferably carried out at 130°C for 6 hours, and then at 190°C for 10 hours.

[0032] In S3, the polymerization reaction can further comprise a post-treatment step. The post-treatment step can be conventional for such reactions in the art, and preferably comprises dissolution and purification.

[0033] The present application also provides a method for preparing an additive, wherein the method is as described above.

[0034] In the photoresist, the amount of the photoacid generator can be conventional in the art, and is preferably 2-10 parts by weight, for example, 4 parts.

[0035] In the photoresist, the photoacid generator can be conventional for such reactions in the art, and is preferably a sulfur salt, for example,

[0036] The weight average molecular weight of the resin of formula (L) in the photoresist can be conventional in the art, and is preferably 8000 to 9000, for example 8500.

[0037] The amount of the resin of formula (L) in the photoresist can be conventional in the art, and is preferably 20 to 120 parts by weight, for example 100 parts.

[0038] The amount of the additive of formula I in the photoresist can be conventional in the art, and is preferably 0.1 to 1 parts by weight, for example 0.5 parts.

[0039] The amount of the solvent in the photoresist can be conventional in the art, and is preferably 500 to 2000 parts by weight, for example 1000 parts.

[0040] The solvent in the photoresist can be conventional in the art, and is preferably an ester solvent, for example propylene glycol methyl ether acetate.

[0041] The photoresist comprises the following raw materials in parts by weight: 4 parts of a photoacid generator, 100 parts of a resin of formula (L), 0.5 parts of an additive of formula I, and 1000 parts of a solvent.

[0042] The photoresist is composed of the following raw materials: the compound of formula I, the resin, the photoacid generator, and the solvent.

[0043] The resin of formula L in the photoresist is prepared by polymerizing an unsaturated acid ester in an organic solvent in the presence of an initiator.

[0044] The unsaturated acid ester in the photoresist can be conventional in the art, and is preferably one or more of the following compounds, for example: one or more of 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionic acid tert-butyl ester, 1-methyladamantyl acrylate, and γ-butyrolactone acrylate; more preferably a mixture of 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionic acid tert-butyl ester, 1-methyladamantyl acrylate, and γ-butyrolactone acrylate. In the mixture, the molar ratio of the three is preferably 1:1:1.

[0045] The organic solvent can be conventional in the art, and is preferably an ether solvent, for example 1,4-dioxane.

[0046] The initiator can be conventional in the art, and is preferably azobisisobutyronitrile.

[0047] The photoresist is prepared by the following method: mixing 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionic acid tert-butyl ester, 1-methyladamantane propenoic acid ester and γ-butyrolactone propenoic acid ester with 1,4-dioxane, adding azobisisobutyronitrile as an initiator, precipitating with n-hexane and drying.

[0048] The application further provides a preparation method of the photoresist, which comprises the following steps: uniformly mixing the resin, the photoacid generator and the additive represented by formula I in a solvent.

[0049] In the preparation method, the solvent, the resin, the photoacid generator and the additive represented by formula I are as described above.

[0050] In the preparation method, the mixing mode can be a conventional mixing mode in the art, and preferably is oscillation.

[0051] In the preparation method, the mixing step preferably further comprises membrane filtration, for example, 0.2 μm membrane filtration.

[0052] The application further provides application of the photoresist in a photoetching process.

[0053] The photoetching process preferably comprises the following steps: coating the photoresist on a pretreated substrate, drying (for example, drying at 110 ℃ for 90 seconds), exposing and developing (for example, using an aqueous solution of tetramethylammonium hydroxide as a developing solution).

[0054] In the application, the weight average molecular weight and the molecular weight distribution index can be measured by a conventional testing method in the art, for example, gel permeation chromatography (GPC).

[0055] On the basis of common knowledge in the art, the above-mentioned preferred conditions can be combined at will, thereby obtaining various preferred examples of the application.

[0056] In the application, normal temperature refers to 10-40 ℃, and normal pressure refers to 98 kPa-103 kPa.

[0057] The reagents and raw materials used in the application are commercially available.

[0058] The photoresist additive of the application improves the problem of material being immersed in water during immersion photoetching exposure, thereby forming a photoresist film micro-pattern with excellent sensitivity and high resolution. DETAILED DESCRIPTION

[0059] The application will be further illustrated by the following examples without thereby limiting the application to the examples described. The experimental methods in the following examples, unless otherwise specified, are carried out according to the conventional methods and conditions, or according to the commercial instructions.

[0060] In the following operations, unless otherwise specified, the temperature and pressure are carried out at room temperature and normal pressure.

[0061] Preparation of the additive of Example 1

[0062] 1. Acetal reaction

[0063] A mixture of L-dimethyltartrate (9.18 g, 1 eq, 0.05 mol), compound B1 (1 eq, 0.05 mol) and p-toluenesulfonic acid (250 mg) was refluxed in toluene (Dean-Stark water trap, 0.6 ml of water) for 48 hours. The solution was cooled and washed with aqueous sodium bicarbonate (5%, 2 x 100 ml), water (100 ml) and brine (100 ml). The organic layer was dried (MgSO4), filtered and the solvent was removed under reduced pressure to give compound C1 (2,3-bicyclo[2,2,1]hept-5-en-2-one-L-dimethyltartrate) as a water-free liquid in 91% yield. 2. Ester hydrolysis reaction

[0064] Compound C1 (0.01 mol) prepared in Example 1 was dissolved in a mixture of NMP (20 ml) and 30% aqueous potassium hydroxide solution (potassium hydroxide (3 g), water (10 g)). The reaction mixture was heated to reflux for 6 hours and the mixture was slowly neutralized by adding dilute hydrochloric acid. Compound D1 (2,3-bicyclo[2,2,1]hept-5-en-2-one-L-tartaric acid) was isolated by column chromatography using ethyl acetate as the eluent and the product was a white waxy solid which was used directly in the next step.

[0065] 3. Polymerization reaction

[0066] Compound D1 (0.01 mol) prepared in Example 2 and 4-dimethylaminopyridine (12 mg, 0.01 mmol) were dissolved in acetic anhydride (5 g, 0.05 mol) and the mixture was stirred at 130°C for 6 hours. The temperature was then raised to 190°C and stirred for about 10 hours, after which the acetic acid was removed under reduced pressure. The solid product was dissolved in DMSO and purified by precipitation into toluene to give polymer A1 (an additive as shown in formula I) with a molecular weight Mw of 1970 and Mw / Mn = 1.1 as determined by GPC.

[0067] Preparation of the resin of Example 2

[0068] Preparation of the resin of Example 2

[0069] tert-Butyl 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropanoate (hereinafter referred to as BHP), 1-methyladamantane acrylate, and γ-butyrolactone acrylate were added at a molar ratio of 1:1:1. With respect to 100 parts by weight of the total amount of the reaction monomers, 300 parts by weight of 1,4-dioxane was added as a polymerization reaction solvent, and with respect to 100 parts by mole of the total amount of the reaction monomers, 4 parts by mole of azobisisobutyronitrile was added as an initiator, and the mixture was allowed to react at 65°C for 16 hours. After the reaction, the reaction solution was precipitated with n-hexane, the precipitate was removed, and vacuum drying was performed. Thereby, a resin as shown in Formula (L) was obtained, and the weight average molecular weight thereof was about 8500 g / mole.

[0070]

[0071] Photoresist preparation example

[0072] 100 parts by weight of the resin as shown in Formula (L), 4 parts by weight of a photoacid generator PAG X, and 0.5 parts by weight of the additive as shown in Formula I were dissolved in 1000 parts by weight of propylene glycol methyl ether acetate, and then the solution was filtered through a 0.2 μm membrane filter. Thereby, a photoresist was prepared.

[0073] Comparative example 1

[0074] Compound B1 in step 1 of Example 1 was replaced with compound B2 to prepare compound C2, and ester hydrolysis and polymerization reactions were successively performed with reference to steps 2 and 3 of Example 1 to prepare polymer A2, and the molecular weight Mw thereof was 2100 and Mw / Mn = 1.2 as measured by GPC.

[0075]

[0076] Comparative example 2

[0077] Compound B1 in step 1 of Example 1 was replaced with B3 to prepare compound C3, and ester hydrolysis and polymerization reactions were successively performed with reference to steps 2 and 3 of Example 1 to prepare polymer A3, and the molecular weight Mw thereof was 1840 and Mw / Mn = 1.0 as measured by GPC.

[0078]

[0079] Effect example

[0080] A bottom anti-reflective coating (BARC, AR40A-900, Rohm & Haas Electronic Materials) having a thickness of 90 nm was formed on a silicon substrate, and the photoresist composition prepared above was coated on the substrate having the BARC. The substrate was baked at 110°C for 60 seconds to form a photoresist film having a thickness of 120 nm.

[0081] The thickness change of each photoresist film before and after development was measured by developing the silicon substrate having the photoresist film with a 2.38 wt% aqueous solution of trimethylammonium hydroxide (TMAH) and measuring the thickness of the photoresist film.

[0082] The slide angle and the receding contact angle of the photoresist film were measured, respectively.

[0083] Specifically, 50 μl of pure water was dropped on the silicon substrate having the photoresist film kept horizontal to form a droplet. While the silicon substrate was gradually tilted, the angle at which the droplet started to slide down (slide angle) and the receding contact angle were determined.

[0084] Then, for liquid immersion lithography, the exposed photoresist film was washed with pure water for 5 minutes. That is, exposure was performed using an ArF scanner 306C (Nikon Corp., NA = 0.78, 6% half-tone mask) and the substrate was washed with pure water for 5 minutes. Exposure was performed at 110°C for 60 seconds, PEB was performed, and development was performed using a 2.38 wt% TMAH developer for 60 seconds.

[0085] The silicon substrate was cut to evaluate the sensitivity. The sensitivity corresponds to the exposure amount used to form a line-and-space (L / S) pattern of 65 nm line width and line space with a line width to line space ratio of 1:1.

[0086] Table 1

[0087]

[0088]

[0089] Conclusion: Referring to Table 1, the photoresist film formed using the photoresist containing the additive prepared in the examples had a higher slide angle and a higher receding contact angle than the photoresist film formed using the photoresist composition prepared in the comparative examples. In addition, the photoresist film prepared in the examples had excellent sensitivity after liquid immersion lithography, but a pattern was not formed on the photoresist film formed in the comparative examples.

Claims

1. A photoresist, comprising the following raw materials: an additive as shown in formula I, a resin as shown in formula (L), a photoacid generator and a solvent; the weight average molecular weight of the additive is 1000-3000; the weight average molecular weight / number average molecular weight ratio of the additive is 1-5. ; （L）； The resin as shown in formula L is prepared by polymerization of a mixture of 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionic acid tert-butyl ester, 1-methyladamantyl acrylate and γ-butyrolactone acrylate in an organic solvent in the presence of an initiator. In the mixture, the molar ratio of the three is 1:1:1; The weight average molecular weight of the resin as shown in formula (L) is 8000-9000; the additive as shown in formula I is: ； The preparation method of the additive comprises the following steps: S1: in an organic solvent, compound B1 is subjected to an acetal reaction with L- dimethyl tartaric acid and p-toluenesulfonic acid to obtain compound C1; the compound B1 is ; S2: in a solvent, under the action of a base, the compound C1 is subjected to ester hydrolysis reaction to obtain compound D1; S3: in an organic solvent, the compound D1 is subjected to polymerization reaction with 4-dimethylaminopyridine to obtain the additive as shown in formula I.

2. The photoresist of claim 1, wherein, In the photoresist, the proportion of the photoacid generator is 2-10 parts by weight; And / or, in the photoresist, the photoacid generator is a sulfur salt; And / or, in the photoresist, the proportion of the resin as shown in formula (L) is 20-120 parts by weight; And / or, in the photoresist, the proportion of the additive as shown in formula I is 0.1-1 parts by weight; And / or, in the photoresist, the proportion of the solvent is 500-2000 parts by weight; And / or, in the photoresist, the solvent is an ester solvent; And / or, in the photoresist, it comprises the following raw materials by weight: 4 parts of a photoacid generator, 100 parts of a resin as shown in formula (L), 0.5 parts of the additive as shown in formula I and 1000 parts of a solvent; And / or, the photoresist is composed of the following raw materials: the compound as shown in formula I, the resin, the photoacid generator and the solvent.

3. The photoresist of claim 1, wherein, The weight average molecular weight of the additive is 1500-2500; And / or, the weight average molecular weight / number average molecular weight ratio of the additive is 1-2; And / or, in the photoresist, the proportion of the photoacid generator is 4 parts by weight; And / or, in the photoresist, the photoacid generator is ; And / or, in the photoresist, the weight average molecular weight of the resin as shown in formula (L) is 8500; And / or, in the photoresist, the proportion of the resin as shown in formula (L) is 100 parts by weight; And / or, in the photoresist, the proportion of the additive as shown in formula I is 0.5 parts by weight; And / or, in the photoresist, the proportion of the solvent is 1000 parts by weight; And / or, in the photoresist, the solvent is propylene glycol methyl ether acetate.

4. The photoresist of claim 3, wherein, The weight average molecular weight of the additive is 1940; And / or, the weight average molecular weight / number average molecular weight ratio of the additive is 1.

1.

5. The photoresist of claim 1, wherein, In the preparation method of the additive, in S3, the organic solvent is an acid anhydride solvent; And / or, in the preparation method of the additive, in S3, the molar ratio of 4-dimethylaminopyridine to the compound D1 is 0.0006-0.0012:

1. And / or, the additive preparation method, S3, the molar ratio of the organic solvent to the compound D1 is 3:1~7:1; And / or, the additive preparation method, S3, the polymerization reaction time is 3~15 hours; And / or, the additive preparation method, S3, the polymerization reaction temperature is 100~200℃; And / or, the photoresist, the resin represented by formula L is prepared by the following method: 3-bicyclo[2.2.1]hept-5-ene-2-yl-3-hydroxypropyl tert-butyl ester, 1-methyladamantane propenoate and γ-butyrolactone propenoate are dissolved in 1,4-dioxane, azobisdimethylamide is added as an initiator, and n-hexane is precipitated and dried.

6. The photoresist of claim 1, wherein, The additive preparation method, S3, the organic solvent is acetic anhydride; And / or, the additive preparation method, S3, the molar ratio of the 4-dimethylamino pyridine to the compound D1 is 0.001:1; And / or, the additive preparation method, S3, the molar ratio of the organic solvent to the compound D1 is 5:1; And / or, the additive preparation method, S3, the polymerization reaction time is 6~10 hours; And / or, the additive preparation method, S3, the polymerization reaction is reacted at 130℃ for 6 hours, and then reacted at 190℃ for 10 hours.

7. A method of preparing a photoresist according to any one of claims 1 to 6, comprising the steps of: The resin, the photoacid generator, and the additive represented by formula I are uniformly mixed in a solvent.

8. The production method according to claim 7, wherein The mixing method is shaking; And / or, the mixing also includes membrane filtration.

9. The production method according to claim 8, wherein The mixing also includes membrane filtration, and the membrane filtration is 0.2μm membrane filtration.

10. The photoresist in the photoetching process, the photoresist is as claimed in any one of claims 1~6.

11. Use according to claim 10, wherein the compound is ###0005### The photoetching process includes the following steps: the photoresist is coated on the pretreated substrate, dried, exposed, and developed.

12. The use according to claim 11, wherein the compound is ###00009### The photoetching process includes the following steps: the photoresist is coated on the pretreated substrate, dried, exposed, and developed; the drying is 110℃ drying for 90 seconds.

13. The use according to claim 11, wherein the compound is ###0007### The photoetching process includes the following steps: the photoresist is coated on the pretreated substrate, dried, exposed, and developed; the developing is using the developing solution as the aqueous solution of tetramethylammonium hydroxide.

Images