CN116144014A

CN116144014A - 193nm dry photoresist additive and preparation method and application thereof

Info

Publication number: CN116144014A
Application number: CN202111393432.XA
Authority: CN
Inventors: 方书农; 王溯; 耿志月
Original assignee: Shanghai Xinyang Semiconductor Material Co Ltd; Shanghai Xinke Micro Material Technology Co Ltd
Current assignee: Shanghai Xinyang Semiconductor Material Co Ltd; Shanghai Xinke Micro Material Technology Co Ltd
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2023-05-23

Abstract

The invention discloses an additive for 193nm dry photoresist, a preparation method and application thereof. Specifically discloses an additive shown as a 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 invention has at least the following advantages: the photoresist containing the additive can form photoresist film micropatterns with excellent sensitivity and high resolution.

Description

193nm dry photoresist additive and preparation method and application thereof

Technical Field

The invention relates to an additive for 193nm dry photoresist, a preparation method and application thereof.

Background

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 having an NA of 1.0 or more is used, a pattern can be formed using the refractive index of water at 193nm, and this method is generally called immersion lithography. However, since the photoresist film is directly contacted 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, development of a photoresist resin or an additive capable of improving such a situation has been desired.

In the microelectronics industry, as well as other industries including microstructure fabrication (e.g., micromachines, magnetoresistive heads, etc.), there is a continuing desire to reduce the size of structural components. In the microelectronics industry, it is desirable to reduce the size of microelectronic devices and/or to provide an increased number of circuits for a given chip size. The ability to fabricate smaller devices is limited by the ability of photolithography to reliably resolve smaller features and gaps. The lens properties allow the ability to produce finer resolution to be limited in part by the wavelength of the light waves (or other radiation) used to form the lithographic pattern. Thus, the use of shorter wavelengths in photolithography is always an ongoing trend. With the recent years of large-scale integrated circuits (Large Scale Integration, LSI) having higher integration and higher speed, accurate micropatterning of a 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.

Although some photoresist compositions have been designed for 193nm radiation applications, these compositions generally exhibit the real advantage of not having shorter wavelength imaging resolution due to the lack of performance in one or more of the above-described areas. Therefore, there is a need to develop photoresist compositions that can be applied to imaging of shorter wavelength radiation (such as 193nm ultraviolet radiation) and that have good developability.

Disclosure of Invention

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

The invention mainly solves the technical problems through the following technical means.

The invention provides an additive shown as a formula I; the weight average molecular weight of the additive is 1000 to 3000, preferably 1500 to 2500, more preferably 1988; the weight average molecular weight/number average molecular weight ratio of the additive is 1 to 5, preferably 1 to 2, more preferably 1.2;

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in one embodiment, the method for preparing the additive preferably comprises the following steps:

s1: in an organic solvent, the compound B1 is subjected to an acetalization reaction with dimethyl L-tartrate and p-toluenesulfonic acid to obtain a compound C1 (bicyclo [ 3.2.1)]Octane-2, 4-dione-L-dimethyl tartrate); the compound B1 is

S2: in a solvent, under the action of alkali, carrying out ester hydrolysis reaction on the compound C1 to obtain a compound D1 (bicyclo [3.2.1] octane-2, 4-diketone-L-tartaric acid);

s3: and (3) in an organic solvent, carrying out polymerization reaction on the compound D1 and 4-dimethylaminopyridine to obtain the additive shown in the formula I.

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

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

In S1, the molar ratio of the compound B1 to the p-toluene sulfonic acid may be conventional in the art, preferably 1: (0.02-0.04), e.g., 1:0.029.

In S1, the post-treatment step of the acetalization reaction may be a conventional post-treatment step in the art, preferably comprising washing, drying, filtering and removing the solvent. The washing solvent may be conventional in the art, preferably washing with aqueous sodium bicarbonate, water and brine in that order. The drying is preferably magnesium sulfate drying.

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

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

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

In S2, the base may be a conventional base in the art, preferably an inorganic base, such as potassium hydroxide and/or sodium hydroxide, preferably potassium hydroxide.

In S2, the molar volume ratio of the compound C1 to the solvent may be conventional in the art, preferably 0.1 to 0.7mol/L, for example 0.5mol/L.

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

In S2, after the ester hydrolysis reaction is finished, a post-treatment step may be further included. The post-treatment step may be conventional in the art, preferably comprising a neutralization and purification operation. The purification step is preferably performed by a chromatography, more preferably by using ethyl acetate as an eluent in the chromatography.

In S2, the time of the ester hydrolysis reaction is preferably 3 to 15 hours, for example, 6 hours, based on the fact that the reaction is not performed any more.

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

In S3, the organic solvent may be an organic solvent commonly used in such reactions in the art, preferably an anhydride-based solvent, such as acetic anhydride.

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

In S3, the molar ratio of the organic solvent to the compound D1 may be conventional in the art, preferably 3:1 to 7:1, for example 5:1.

In S3, the polymerization reaction is preferably carried out for a period of time of 3 hours to 20 hours, for example, 6 hours to 16 hours, based on the fact that the reaction is not carried out any more.

In S3, the polymerization reaction temperature may be conventional in the art, preferably 100 to 200℃such as 130 to 190 ℃.

S3, the polymerization reaction is carried out in two steps, wherein the first step is carried out at 100-140 ℃ for 6-8 hours, and the second step is carried out at 160-200 ℃ for 10-12 hours; the polymerization is carried out in two steps, preferably the first step is carried out at 130℃for 6 hours and the second step is carried out at 190℃for 10 hours.

In S3, the polymerization reaction may further include a post-treatment step; the post-treatment step may be conventional in the art, preferably involving solubilization and purification operations.

The invention also provides a preparation method of the additive, and the preparation method of the additive is as described above.

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

the photoresist may be used in an amount conventional in the art, wherein the parts by weight are preferably 2 to 10 parts, for example, 4 parts.

In the photoresist, the photoacid generator may be conventional in the art, preferably a sulfur salt, e.g

In the photoresist, the weight average molecular weight of the resin represented by the formula (L) may be conventional in the art, preferably 8000 to 9000, for example 8500.

In the photoresist, the resin represented by the formula (L) may be used in an amount conventional in the art, wherein the parts by weight are preferably 20 to 120 parts, for example, 100 parts.

The additives of formula I may be used in amounts conventional in the art, wherein the parts by weight are preferably 0.1 to 1 part, for example 0.5 part.

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

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

The photoresist preferably comprises the following raw materials in parts by weight: 4 parts of photoacid generator, 100 parts of resin shown as a formula (L), 0.5 part of additive shown as a formula I and 1000 parts of solvent.

The photoresist is preferably composed of the following raw materials: the compound shown as the formula I, the resin, the photoacid generator and the solvent.

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

The polymerization reaction can also comprise a post-treatment step; the post-treatment step may be conventional in the art, preferably including precipitation and drying.

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

In the photoresist, the preparation method of the resin shown in the formula (L) preferably comprises the following steps: 3-bicyclo [2.2.1] hept-5-en-2-yl-3-hydroxy-propionic acid tert-butyl ester, 1-methyladamantane acrylate and gamma-butyrolactone acrylate with a molar ratio of 1:1:1 are mixed to form a mixture of 100 parts by weight, the mixture is dissolved in 300 parts by weight of 1, 4-dioxane, 4 parts by weight of azodiisobutyronitrile is added as an initiator, the mixture is reacted for 16 hours at 65 ℃, normal hexane is precipitated, and the precipitate is removed and dried in vacuum.

The invention also provides a preparation method of the photoresist, which preferably comprises the following steps: and (3) in a solvent, uniformly mixing the resin shown in the formula (L), the photoacid generator and the additive shown in the formula I.

In the preparation method, the solvent, the resin shown in the formula (L), the photoacid generator and the additive shown in the formula I are as described above.

In the preparation method, the mixing mode can be a mixing mode conventional in the field, and vibration is preferred.

In the preparation method, the mixing step preferably further comprises filtration with a filter membrane, for example, a 0.2 μm filter membrane.

The invention also provides application of the photoresist in a photoetching process.

Wherein, the photoetching process preferably comprises the following steps: the photoresist is coated on a pretreated substrate, dried (e.g., at 110 ℃ for 90 seconds), exposed to light, and developed (e.g., using a developer solution that is an aqueous solution of tetramethylammonium hydroxide).

In the present invention, the weight average molecular weight and molecular weight distribution index can be measured by a conventional test method in the art, such as Gel Permeation Chromatography (GPC).

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

In the present invention, normal temperature means 10 to 40 ℃, and normal pressure means 98 to 103kPa.

The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that: the photoresist containing the additive shown in the formula I can form a photoresist film micropattern with excellent sensitivity and high resolution.

Detailed Description

The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

In the following operations, the temperature and pressure are not particularly specified, and the operations are carried out at normal temperature and normal pressure.

Example 1 preparation of additives

Dimethyl L-tartrate (9.18 g, 1 eq, 0.05 mol), compound B1

A mixture of (1 eq, 0.05 mole) and p-toluene sulfonic acid (250 mg) was refluxed in toluene for 48 hours (dean-stark water separator, 0.6 ml of water). The solution was cooled and washed with aqueous sodium bicarbonate (5%, 2×100 ml), water (100 ml) and brine (100 ml). The organic layer was dried (MgSO ₄ ) Filtering and removing the solvent under reduced pressure to give compound C1 (bicyclo [ 3.2.1)]Octane-2, 4-dione-L-dimethyl tartrate) as an anhydrous liquid in 91% yield.

2. Ester hydrolysis reaction

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 the addition of dilute hydrochloric acid. The compound D1 (bicyclo [3.2.1] octane-2, 4-dione-L-tartaric acid) is separated by column chromatography, ethyl acetate is used as an eluent, and the product is white waxy solid which can be directly used in the next step.

3. Polymerization reaction

Compound D1 (0.01 mol) and 4-dimethylaminopyridine (12 mg, 0.01 mmol) prepared in example 2 were dissolved in acetic anhydride (5 g, 0.05 mol) and the mixture was stirred at 130 ℃ for 6 hours. The temperature was then raised to 190 ℃ and stirred for about 10 hours, after which acetic acid was removed under reduced pressure. Cooling to room temperature, dissolving the solid product in DMSO, precipitating into toluene, and purifying to obtain polymer A1 (additive shown as formula I), having a GPC molecular weight Mw of 1988, mw/mn=1.2.

EXAMPLE 2 preparation of resin

3-bicyclo [2.2.1] hept-5-en-2-yl-3-hydroxypropionate (hereinafter referred to as BHP), 1-methyladamantane acrylate and gamma-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 with respect to 100 parts by weight of the total amount of the reaction monomers, 4 parts by mole of azobisisobutyronitrile was added as an initiator with respect to 100 parts by mole of the total amount of the reaction monomers, and the mixture was reacted at 65℃for 16 hours. After the reaction, the reaction solution was precipitated with n-hexane, and the precipitate was removed and dried in vacuo. Thus, a resin represented by the formula (L) was obtained, which had a weight average molecular weight of about 8500g/mol.

Photoresist preparation examples

100 parts by weight of a resin represented by the formula (L), 4 parts by weight of a photoacid generator PAGX, and 0.5 parts by weight of an additive represented by the 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.

Comparative example 1

The compound B1 in step 1 of example 1 was replaced with the compound B2 to obtain the compound C2, and ester hydrolysis and polymerization were sequentially carried out with reference to steps 2 and 3 of example 1 to obtain the polymer A2, which had a GPC detection molecular weight Mw of 2100, mw/mn=1.2.

Comparative example 2

The compound B1 in step 1 of example 1 was replaced with B3 to obtain compound C3, and ester hydrolysis and polymerization were performed sequentially with reference to steps 2 and 3 of example 1 to obtain polymer A3, having a GPC detection molecular weight Mw of 1840, mw/mn=1.0.

Effect examples

An anti-reflective primer layer (BARC, AR40A-900, rogowski electronic materials Co., ltd.) having a thickness of 90nm was formed on a silicon substrate, and the photoresist composition prepared as described above was coated on the substrate having the BARC. The substrate was baked at 110 ℃ for 60 seconds to form a photoresist film having a thickness of 120 nm.

The thickness variation of each photoresist film before and after development was measured by developing a 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.

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

The silicon substrate was cut to evaluate sensitivity. Sensitivity corresponds to a sensitivity for a ratio of linewidth to line spacing of 1:1 an exposure dose forming a line-and-space (L/S) pattern of 65nm line width.

TABLE 1

Photoresist film	Additive agent	Thickness (nm) of film after development	Sensitivity (mJ/cm) ² )
				Photoresist preparation example 1	Polymer A1	4	46
Photoresist preparation example 2	Polymer A2	4	Pattern free formation
				Photoresist preparation example 3	Polymer A3	4	Pattern free formation

Referring to table 1, after photolithography, a photoresist film formed using the photoresist composition comprising the photoresist additive prepared in the example had superior sensitivity to a photoresist film formed using the photoresist composition comprising the photoresist additive prepared in the comparative example, and no pattern was formed on the photoresist film formed using the comparative example.

Claims

1. An additive of 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;

2. the additive of claim 1, wherein the weight average molecular weight of the additive is from 1500 to 2500;

and/or the weight average molecular weight/number average molecular weight ratio of the additive is 1-2.

3. The additive of claim 1, wherein 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, wherein the preparation method of the additive comprises the following steps:

s1: carrying out an acetal reaction on the compound B1, L-dimethyl tartrate and p-toluenesulfonic acid in an organic solvent to obtain a compound C1; the compound B1 is

S2: in a solvent, under the action of alkali, carrying out ester hydrolysis reaction on the compound C1 to obtain a compound D1;

5. The additive of claim 4, wherein in S1, the organic solvent is an aromatic 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 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 0.1-0.7 mol/L;

and/or, in S2, the time of the ester hydrolysis reaction is 3-15 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 3:1-7:1;

and/or, in S3, the time of the polymerization reaction is 3-20 hours;

and/or, in S3, the temperature of the polymerization reaction is 100-200 ℃.

6. The additive of claim 4, wherein in S1, the organic solvent is toluene;

and/or, in S1, the molar ratio of the compound B1 to the L-dimethyl 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-methyl pyrrolidone;

and/or, in S2, the alkali is potassium hydroxide and/or sodium hydroxide;

and/or, in S2, the molar volume ratio of the compound C1 to the solvent is 0.5mol/L;

and/or, in S2, the time of the ester hydrolysis reaction 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 time of the polymerization reaction is 6-16 hours;

and/or, in S3, the temperature of the polymerization reaction is 130-190 ℃.

7. The additive according to claim 4, wherein in S2, the alkali participates in the reaction in the form of an aqueous alkali solution, and the mass ratio of the alkali to the water is 0.1:1-0.6:1;

and/or S3, the polymerization reaction is carried out in two steps, wherein the first step is carried out at 100-140 ℃ for 6-8 hours, and the second step is carried out at 160-200 ℃ for 10-12 hours.

8. The additive of claim 4, wherein in S2, the base participates in the reaction as an aqueous base, the mass ratio of base to water being 0.3:1;

and/or, in S3, the polymerization reaction is carried out in two steps, wherein the first step is carried out at 130 ℃ for 6 hours, and the second step is carried out at 190 ℃ for 10 hours.

9. The additive according to any one of claims 4 to 8, wherein in S1, the temperature of the acetalization reaction is the solvent reflux temperature at normal temperature and normal pressure of the solvent;

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 normal pressure.

10. A method for producing an additive, characterized in that the operations and conditions of the production method are the same as those of the additive according to any one of claims 4 to 9.