A 193nm dry-process photoresist additive and its preparation method and application

Abstract

The present invention discloses an additive for 193nm dry photoresist, a preparation method and application thereof. Specifically disclosed is an additive as shown in formula I; 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. The additive of the present invention has at least the following advantages: the photoresist containing the additive can form a photoresist film micro pattern with excellent sensitivity and high resolution.

Description

Technical Field

[0001] The invention relates to an additive for 193nm dry-process photoresist and a preparation method and application thereof. Background Art

[0002] In ArF dry lithography using ArF excimer laser as a light source, the space between the projection lens and the wafer substrate is filled with water. According to this method, even if a lens with an NA of 1.0 or more is used, a pattern can be formed using the refractive index of water at 193 nm, and this method is generally referred to as immersion lithography. However, since the photoresist film is in direct contact with water, the photoresist pattern may be deformed or may collapse due to swelling, or various defects such as bubbles and watermarks may be generated. For this reason, it is urgent to develop a photoresist resin or additive that can improve this situation.

[0003] In the microelectronics industry and other industries including microstructure manufacturing (e.g., micromachines, magnetoresistive heads, etc.), it is always desirable to reduce the size of structural components. In the microelectronics industry, it is desirable to reduce the size of microelectronic devices and / or provide more circuit numbers for a given chip size. The ability to manufacture smaller devices is limited by the ability of photolithography to reliably distinguish smaller features and gaps. The lens properties make the ability to produce finer resolution limited to some extent by the wavelength of the light wave (or other radiation) used to form the photolithographic pattern. Therefore, the application of shorter light wavelengths in the photolithographic process has always been a trend that is being promoted. With the large-scale integrated circuit (LSI) having higher integration and higher speed in recent years, accurate micropatterning of photoresist is required. As the exposure light source used in forming the resist pattern, ArF light source (193nm) or KrF light source (248nm) has been widely used.

[0004] Although some photoresist compositions have been designed for 193 nm radiation use, these compositions generally do not demonstrate the true advantages of shorter wavelength imaging resolution due to the lack of performance in one or more of the above-mentioned areas. Therefore, it is urgent to develop photoresist compositions that can be used for shorter wavelength radiation imaging (such as 193 nm ultraviolet radiation) and have good developability. Summary of the invention

[0005] In order to overcome the problem of the limitation of the application of short wavelength radiation imaging in LSI in the prior art, the present invention provides an additive for 193nm dry photoresist and its preparation method and application. The additive of the present invention is used in the photoresist, so that the photoresist has the advantages of being applicable to shorter wavelength radiation imaging and having good developing properties.

[0006] The present invention mainly solves the above technical problems through the following technical means.

[0007] The present invention provides an additive as shown in formula I; the weight average molecular weight of the additive is 1000-3000, preferably 1500-2500, more preferably 1988; the weight average molecular weight / number average molecular weight ratio of the additive is 1-5, preferably 1-2, more preferably 1.2;

[0008]

[0009] In a certain embodiment, the method for preparing the additive preferably comprises the following steps:

[0010] S1: In an organic solvent, compound B1 is subjected to an acetal reaction with dimethyl L-tartrate and p-toluenesulfonic acid to obtain compound C1 (bicyclo[3.2.1]octane-2,4-dione-dimethyl L-tartrate); the compound B1 is

[0011] S2: In a solvent, under the action of a base, subjecting the compound C1 to an ester hydrolysis reaction to obtain a compound D1 (bicyclo[3.2.1]octane-2,4-dione-L-tartaric acid);

[0012] S3: In an organic solvent, the compound D1 is polymerized with 4-dimethylaminopyridine to obtain an additive as shown in formula I.

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

[0014] In S1, the molar ratio of the compound B1 to the dimethyl L-tartrate can be conventional in the art, preferably 1:(1-1.5), for example 1:1.

[0015] In S1, the molar ratio of the compound B1 to the p-toluenesulfonic acid can be conventional in the art, preferably 1:(0.02-0.04), for example 1:0.029.

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

[0017] In S1, the reaction time of the acetalization reaction is based on the complete reaction of the reactants, preferably 26 hours to 60 hours, for example 48 hours.

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

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

[0020] In S2, the base can be a conventional base 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 in the art, preferably 0.1 to 0.7 mol / L, such as 0.5 mol / L.

[0022] In S2, the base is preferably added to the reaction in the form of an aqueous base solution. The mass ratio of the base to water is preferably 0.1:1 to 0.6:1, for example 0.3:1.

[0023] In S2, after the ester hydrolysis reaction is completed, a post-treatment step may be further included. The post-treatment step may be conventional in the art, preferably including neutralization and purification operations. The purification step preferably uses a chromatographic column method, and more preferably ethyl acetate is used as an eluent in the chromatographic column method.

[0024] In S2, the ester hydrolysis reaction time is based on the reaction not proceeding any more, preferably 3 hours to 15 hours, for example 6 hours.

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

[0026] In S3, the organic solvent may be a commonly used organic solvent for this type of reaction in the art, preferably an anhydride solvent, such as acetic anhydride.

[0027] In S3, the molar ratio of the 4-dimethylaminopyridine to the compound D1 can be conventional in the art, preferably 1:(900-1500), for example 1:1000.

[0028] In S3, the molar ratio of the organic solvent to the compound D1 can be conventional in the art, preferably 3:1 to 7:1, such as 5:1.

[0029] In S3, the polymerization reaction time is based on the reaction not proceeding any more, preferably 3 hours to 20 hours, for example 6 hours to 16 hours.

[0030] In S3, the polymerization reaction temperature may be conventional in the art, preferably 100 to 200°C, such as 130 to 190°C.

[0031] In S3, the polymerization reaction is carried out in two steps, the first step is to react at 100-140°C for 6-8 hours, and the second step is to increase the temperature to 160-200°C for 10-12 hours; the polymerization reaction is carried out in two steps, preferably the first step is to react at 130°C for 6 hours, and the second step is to increase the temperature to 190°C for 10 hours.

[0032] In S3, the polymerization reaction may further include a post-treatment step; the post-treatment step may be conventional in the art, and preferably includes dissolution and purification operations.

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

[0034] The present invention also provides a photoresist, which comprises the following raw materials: the additive as shown in formula I, the resin as shown in formula (L), a photoacid generator and a solvent;

[0035]

[0036] In the photoresist, the amount of the photoacid generator used can be conventional in the art, wherein the amount by weight is preferably 2 to 10 parts, such as 4 parts.

[0037] In the photoresist, the photoacid generator can be conventional in the art, preferably a thiosalt, such as

[0038] In the photoresist, the weight average molecular weight of the resin represented by formula (L) can be conventional in the art, preferably 8000 to 9000, such as 8500.

[0039] In the photoresist, the amount of the resin represented by formula (L) can be conventional in the art, wherein the amount in parts by weight is preferably 20 to 120 parts, such as 100 parts.

[0040] In the photoresist, the amount of the additive represented by formula I can be conventional in the art, wherein the amount in parts by weight is preferably 0.1 to 1 part, such as 0.5 part.

[0041] In the photoresist, the amount of the solvent used can be conventional in the art, wherein the amount in parts by weight is preferably 500 to 2000 parts, such as 1000 parts.

[0042] In the photoresist, the solvent may be conventional in the art, preferably an ester solvent, such as propylene glycol methyl ether acetate.

[0043] The photoresist preferably comprises the following raw materials in parts by weight: 4 parts of a photoacid generator, 100 parts of a resin represented by formula (L), 0.5 parts of an additive represented by the above formula I, and 1000 parts of a solvent.

[0044] The photoresist is preferably composed of the following raw materials: the compound as shown in Formula I, the resin, the photoacid generator and the solvent.

[0045] In the photoresist, the preparation method of the resin represented by formula (L) preferably comprises the following steps: in 300 parts by weight of an organic solvent, 100 parts by weight of an unsaturated acid ester is polymerized under the action of 4 parts by weight of an initiator.

[0046] The polymerization reaction may further include a post-treatment step; the post-treatment step may be conventional in the art, and preferably includes precipitation and drying.

[0047] In the photoresist, the unsaturated acid ester may be conventional in the art, preferably one or more of tert-butyl 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionate, 1-methyladamantyl acrylate and γ-butyrolactone acrylate.

[0048] In the photoresist, the preparation method of the resin represented by formula (L) preferably comprises the following steps: mixing tert-butyl 3-bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionate, 1-methyladamantane acrylate and γ-butyrolactone acrylate in a molar ratio of 1:1:1 into a mixture of 100 parts by weight, dissolving the mixture in 300 parts by weight of 1,4-dioxane, adding 4 parts by weight of azobisisobutyronitrile as an initiator, reacting at 65° C. for 16 hours, precipitating with n-hexane, removing the precipitate and vacuum drying.

[0049] The present invention also provides a method for preparing the photoresist, which preferably comprises the following steps: uniformly mixing the resin represented by formula (L), the photoacid generator and the additive represented by formula I in a solvent.

[0050] In the preparation method, the solvent, the resin represented by formula (L), the photoacid generator, and the additive represented by formula I are as described above.

[0051] In the preparation method, the mixing method can be a conventional mixing method in the art, preferably shaking.

[0052] In the preparation method, the mixing step preferably further includes membrane filtration, for example, filtration using a 0.2 μm membrane.

[0053] The present invention also provides an application of the above-mentioned photoresist in a photolithography process.

[0054] The photolithography process preferably includes the following steps: coating the photoresist on a pretreated substrate, drying (eg, drying at 110° C. for 90 seconds), exposing and developing (eg, using a developer of tetramethylammonium hydroxide aqueous solution).

[0055] In the present invention, the weight average molecular weight and molecular weight distribution index can be measured by conventional testing methods in the art, such as gel permeation chromatography (GPC).

[0056] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0057] In the present invention, normal temperature refers to 10 to 40° C., and normal pressure refers to 98 kPa to 103 kPa.

[0058] The reagents and raw materials used in the present invention are commercially available.

[0059] The positive and progressive effect of the present invention is that the photoresist containing the additive as shown in Formula I can form a photoresist film micropattern with excellent sensitivity and high resolution. DETAILED DESCRIPTION

[0060] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0061] In the following operations, unless otherwise specified, all operations are carried out at room temperature and pressure.

[0062] Example 1 Preparation of additives

[0063] L-dimethyl tartrate (9.18 g, 1 equivalent, 0.05 mol), compound B1 A mixture of 1,4-dihydro-1,4-dione-L-tartrate (1 eq., 0.05 mol) and p-toluenesulfonic acid (250 mg) was refluxed in toluene for 48 h (Dean-Stark water separator, 0.6 mL of water). 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 removed under reduced pressure to give compound C1 (bicyclo[3.2.1]octane-2,4-dione-L-tartrate dimethyl ester) as an anhydrous liquid in 91% yield.

[0064] 2. Ester hydrolysis reaction

[0065] 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 dilute hydrochloric acid was added to slowly neutralize the mixture. Compound D1 (bicyclo[3.2.1]octane-2,4-dione-L-tartaric acid) was separated by column chromatography, ethyl acetate was used as the eluent, and the product was a white waxy solid, which could be directly used in the next step.

[0066] 3. Polymerization reaction

[0067] The 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, and then the acetic acid was removed under reduced pressure. After cooling to room temperature, the solid product was dissolved in DMSO and purified by precipitation into toluene to obtain polymer A1 (the additive shown in Formula I), with a molecular weight Mw of 1988 as determined by GPC, and Mw / Mn=1.2.

[0068] Example 2 Preparation of resin

[0069] 3-Bicyclo[2.2.1]hept-5-en-2-yl-3-hydroxypropionic acid tert-butyl ester (hereinafter referred to as BHP), 1-methyladamantane acrylate and γ-butyrolactone acrylate were added in a molar ratio of 1:1:1. 300 parts by weight of 1,4-dioxane was added as a polymerization solvent relative to 100 parts by weight of the total amount of the reaction monomers, 4 parts by mole of azobisisobutyronitrile was added as an initiator relative to 100 parts by mole of the total amount of the reaction monomers, and the mixture was reacted at 65°C for 16 hours. After the reaction, the reaction solution was precipitated with n-hexane, and the precipitate was removed and vacuum dried. Thus, a resin as shown in formula (L) was obtained, and its weight average molecular weight was about 8500 g / mol.

[0070]

[0071] Photoresist preparation example

[0072] 100 parts by weight of the resin represented by formula (L), 4 parts by weight of the photoacid generator PAGX and 0.5 parts by weight of the additive represented by 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 preparing a photoresist.

[0073] Comparative Example 1

[0074] Compound B1 in step 1 of Example 1 was replaced by compound B2 to obtain compound C2, and ester hydrolysis and polymerization were carried out in accordance with steps 2 and 3 of Example 1 to obtain polymer A2. The molecular weight Mw detected by GPC was 2100, and Mw / Mn=1.2.

[0075]

[0076] Comparative Example 2

[0077] Compound B1 in step 1 of Example 1 was replaced by B3 to obtain compound C3, and ester hydrolysis and polymerization were carried out in accordance with steps 2 and 3 of Example 1 to obtain polymer A3. The molecular weight Mw detected by GPC was 1840, and Mw / Mn=1.0.

[0078]

[0079] Effect Example

[0080] An anti-reflective primer layer (BARC, AR40A-900, Rohm and Haas Electronic Materials Co., Ltd.) with a thickness of 90 nm was formed on a silicon substrate, and the photoresist composition prepared above was coated on the substrate with BARC. The substrate was baked at 110° C. for 60 seconds to form a photoresist film with 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 % trimethylammonium hydroxide (TMAH) aqueous solution and measuring the thickness of the photoresist film.

[0082] Exposure was performed using an ArF scanner ASML-1400 at 110° C. for 60 seconds, PEB was performed, and development was performed using a 2.38 wt % TMAH developer for 60 seconds to form a pattern.

[0083] The silicon substrate was cut to evaluate the sensitivity corresponding to the exposure amount for forming a line-and-space (L / S) pattern of 65 nm at a ratio of 1:1.

[0084] Table 1

[0085] Photoresist film additive Thickness of film after development (nm) <![CDATA[Sensitivity (mJ / cm 2 )]]> Photoresist preparation example 1 Polymer A1 4 46 Photoresist preparation example 2 Polymer A2 4 No patterning Photoresist preparation example 3 Polymer A3 4 No patterning

[0086] Referring to Table 1, after photolithography, the photoresist film formed using the photoresist composition including the photoresist additive prepared in the example has excellent sensitivity compared with the photoresist film formed using the photoresist composition including the photoresist additive prepared in the comparative example, and no pattern is formed on the photoresist film formed using the comparative example.

Claims

1. An additive as shown in formula I; the weight average molecular weight of the additive is 1000 to 3000; the weight average molecular weight / number average molecular weight ratio of the additive is 1 to 5; 2. The additive according to claim 1, characterized in that The weight average molecular weight of the additive is 1500 to 2500; And / or, the weight average molecular weight / number average molecular weight ratio of the additive is 1-2.

3. The additive according to claim 1, characterized in that The weight average molecular weight of the additive is 1988; And / or, the weight average molecular weight / number average molecular weight ratio of the additive is 1.

2.

4. The additive according to claim 1, characterized in that The preparation method of the additive comprises the following steps: S1: In an organic solvent, compound B1 is reacted with L-dimethyl tartarate and p-toluenesulfonic acid to obtain compound C1; the compound B1 is S2: In a solvent, under the action of a base, subjecting the compound C1 to an ester hydrolysis reaction to obtain a compound D1; S3: In an organic solvent, the compound D1 is polymerized with 4-dimethylaminopyridine to obtain an additive as shown in formula I.

5. The additive according to claim 4, characterized in that In S1, the organic solvent is an aromatic hydrocarbon solvent; and / or, in S1, the molar ratio of the compound B1 to the dimethyl L-tartrate is 1:(1-1.5); and / or, in S1, the molar ratio of the compound B1 to the p-toluenesulfonic acid is 1:(0.02-0.04); And / or, in S1, the reaction time of the acetalization reaction is 26 hours to 60 hours; and / or, in S2, the solvent is a ketone solvent; and / or, in S2, the base is an inorganic base; and / or, in S2, the molar volume ratio of the compound C1 to the solvent is 0.1 to 0.7 mol / L; And / or, in S2, the ester hydrolysis reaction time is 3 hours to 15 hours; And / or, in S3, the organic solvent is an anhydride solvent; and / or, in S3, the molar ratio of the 4-dimethylaminopyridine to the compound D1 is 1:(900-1500); and / or, in S3, the molar ratio of the organic solvent to the compound D1 is 3:1 to 7:1; And / or, in S3, the polymerization reaction time is 3 hours to 20 hours; And / or, in S3, the polymerization reaction temperature is 100-200°C.

6. The additive according to claim 4, characterized in that In S1, the organic solvent is toluene; And / or, in S1, the molar ratio of the compound B1 to the dimethyl L-tartrate is 1:1; And / or, in S1, the molar ratio of the compound B1 to the p-toluenesulfonic acid is 1:0.029; And / or, in S1, the reaction time of the acetalization reaction is 48 hours; And / or, in S2, the solvent is N-methylpyrrolidone; And / or, in S2, the base is potassium hydroxide and / or sodium hydroxide; and / or, in S2, the molar volume ratio of the compound C1 to the solvent is 0.5 mol / L; And / or, in S2, the ester hydrolysis reaction time is 6 hours; And / or, in S3, the organic solvent is acetic anhydride; and / or, in S3, the molar ratio of the 4-dimethylaminopyridine to the compound D1 is 1:1000; and / or, in S3, the molar ratio of the organic solvent to the compound D1 is 5:1; And / or, in S3, the polymerization reaction time is 6 to 16 hours; And / or, in S3, the polymerization reaction temperature is 130-190°C.

7. The additive according to claim 4, characterized in that In S2, the base is involved in the reaction in the form of an aqueous base solution, and the mass ratio of the base to water is 0.1:1 to 0.6:1; And / or, in S3, the polymerization reaction is carried out in two steps, the first step is to react at 100-140° C. for 6-8 hours, and the second step is to raise the temperature to 160-200° C. for 10-12 hours.

8. The additive according to claim 4, characterized in that In S2, the base is involved in the reaction in the form of an aqueous base solution, and the mass ratio of the base to water is 0.3:1; And / or, in S3, the polymerization reaction is carried out in two steps, the first step is carried out at 130° C. for 6 hours, and the second step is carried out at a temperature of 190° C. for 10 hours.

9. The additive according to any one of claims 4 to 8, characterized in that In S1, the temperature of the acetalization reaction is the reflux temperature of the solvent at normal temperature and pressure; And / or, in S2, the base is potassium hydroxide; And / or, in S2, the temperature of the ester hydrolysis reaction is the reflux temperature of the solvent at normal temperature and pressure.

10. A method for preparing an additive, characterized in that: Preparation of the additive according to any one of claims 4 to 9.

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