CN115960341B

CN115960341B - ArF immersion type additive for photoresist and photoresist containing ArF immersion type additive

Info

Publication number: CN115960341B
Application number: CN202111172184.6A
Authority: CN
Inventors: 王溯; 方书农; 徐森; 邹琴峰
Original assignee: Shanghai Xinke Micro Material Technology Co Ltd
Current assignee: Shanghai Xinke Micro Material Technology Co Ltd
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2024-09-06
Anticipated expiration: 2041-10-08
Also published as: CN115960341A

Abstract

The invention discloses an ArF immersion photoresist additive and photoresist containing the ArF immersion photoresist additive. 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 improve the problem that the material is leached out in water during immersion lithography exposure, so that a photoresist film micropattern with excellent sensitivity and high resolution can be formed.

Description

ArF immersion type additive for photoresist and photoresist containing ArF immersion type additive

Technical Field

The invention relates to an ArF immersion photoresist additive and photoresist containing the ArF immersion photoresist additive.

Background

With the recent years that large scale integrated circuits (LSI) have higher integration and higher speed, accurate micropatterning 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.

In ArF immersion 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.

Disclosure of Invention

In view of the above problems in the prior art, the present invention aims to provide an ArF immersion photoresist additive and a photoresist containing the same, and the additive has at least the following advantages: the photoresist containing the additive can improve the problem that the material is leached out in water during immersion lithography exposure, so that a photoresist film micropattern with excellent sensitivity and high resolution can be formed.

The invention provides an application of a compound shown as a formula I as an additive in photoresist; the weight average molecular weight of the additive may be from 1000 to 3000, preferably from 1500 to 2500 (e.g. 1940); the weight average molecular weight/number average molecular weight ratio of the additive may be from 1 to 5, preferably from 1 to 2 (e.g. 1.1);

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

S1, carrying out an acetal reaction on a compound B1, L-dimethyl tartrate and p-toluenesulfonic acid in an organic solvent to obtain a compound C1 (2, 3-bicyclo [2, 1] hept-5-ene-2-one-L-diethyl 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 (2, 3-bicyclo [2, 1] hept-5-ene-2-one-L-tartaric acid);

and S3, 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 for such reactions in the art, preferably an aromatic solvent such as toluene.

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

In S1, the molar ratio of said compound B1 to said p-toluene sulfonic acid may be conventional in this type of reaction in the art, preferably 1: (20-60), for example 1:38.5.

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 this type of reaction, and is preferably washed with aqueous sodium bicarbonate, water and brine in sequence. 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 this type of reaction in the art, preferably a ketone solvent, such as N-methylpyrrolidone.

In S2, the base may be a conventional base for such reactions 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 this type of reaction in the art, preferably from 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 work-up step may be conventional in this type of reaction in the art, e.g. comprising neutralization and purification operations. 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 this type of reaction in the art, preferably from 0.0006 to 0.0012:1, for example 0.001:1.

In S3, the molar ratio of the organic solvent to the compound D1 may be conventional in this type of reaction 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 15 hours, for example, 6 hours to 10 hours, in order that the reaction is not carried out any more.

In S3, the temperature of the polymerization reaction may be a temperature conventional in such reactions in the art, preferably 100 to 200 ℃.

In S3, the polymerization is preferably carried out at 130℃for 6 hours and then at 190℃for 10 hours.

In S3, the polymerization reaction may further include a post-treatment step. The work-up step may be conventional in this type of reaction, and preferably includes a dissolving and purifying operation.

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 photoacid generator may be used in the photoresist in an amount conventional in this type of reaction, 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 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 consists of the following raw materials: the compound shown as the formula I, the resin, the photoacid generator and the solvent.

In the photoresist, the resin shown in the formula L is prepared by the following method: and polymerizing the unsaturated acid ester in an organic solvent under the action of an initiator.

In the photoresist, the unsaturated acid ester may be conventional in this type of reaction in the art, 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-hydroxypropionate tert-butyl ester, 1-methyladamantane acrylate, and gamma-butyrolactone acrylate; more preferably a mixture of 3-bicyclo [2.2.1] hept-5-en-2-yl-3-hydroxypropionate tert-butyl ester, 1-methyladamantane acrylate and gamma-butyrolactone acrylate. Wherein, the molar ratio of the three in the mixture is preferably 1:1:1.

The organic solvent may be an organic solvent conventional in the art, preferably an ether solvent such as 1, 4-dioxane.

The initiator may be any initiator conventional in the art, such as azobisisobutyronitrile.

In the photoresist, the resin shown as the formula L is prepared by the following method, and the method comprises the following steps: mixing 3-bicyclo [2.2.1] hept-5-en-2-yl-3-hydroxy-propionic acid tert-butyl ester, 1-methyladamantane acrylate, gamma-butyrolactone acrylate and 1, 4-dioxane, adding azodiisobutyronitrile as an initiator, precipitating with n-hexane, and drying.

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

In the preparation method, the solvent, the resin, 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 ℃. The normal pressure is 98kPa to 103kPa.

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

The invention has the positive progress effects that: the photoresist additive improves the problem of leaching of materials in water during immersion lithography exposure, so that a photoresist film micropattern having excellent sensitivity and high resolution can be formed.

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

1. Acetal reaction

Dimethyl L-tartrate (9.18 g, 1eq, 0.05 mol), compound B1A 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), filtered and the solvent removed under reduced pressure to give compound C1 (diethyl 2, 3-bicyclo [2, 1] hept-5-en-2-one-L-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. Separating by column chromatography to obtain compound D1 (2, 3-bicyclo [2, 1] hept-5-ene-2-one-L-tartaric acid), wherein ethyl acetate is used as 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 in toluene, and purifying to obtain polymer A1 (additive shown as formula I), wherein the Mw of GPC is 1970, and Mw/Mn=1.1.

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.

The slip angle and receding contact angle of the photoresist film were measured, respectively.

Specifically, 50 μl of pure water was dropped on the silicon substrate with the photoresist film held horizontally to form droplets. The angle at which the droplet began to slide down (sliding angle) and the receding contact angle were measured while the silicon substrate was gradually inclined.

Then, in order to realize 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% halftone mask), and the substrate was rinsed with pure water for 5 minutes. The exposure was performed at 110 ℃ for 60 seconds, PEB was performed, and development was performed using 2.38 wt% TMAH developer for 60 seconds.

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

TABLE 1

Conclusion: referring to table 1, a photoresist film formed using a photoresist containing the additive prepared in the example has a higher slip angle and a higher receding contact angle than a photoresist film formed using the photoresist composition prepared in the comparative example. In addition, the photoresist film prepared in the examples had excellent sensitivity after liquid immersion lithography, but the pattern was not formed on the photoresist film formed in 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 2, 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.

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 a 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 L-dimethyl tartrate is 1 (1-1.5);

And/or, in S1, the molar ratio of the compound B1 to the p-toluenesulfonic acid is 1: (20-60);

and/or, in S1, the reaction time of the acetalization reaction is 26 to 60 hours.

6. The additive of claim 4, wherein 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.

7. The additive of claim 6, wherein in S2, the base participates in the reaction as an aqueous base.

8. The additive according to claim 6, 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.

9. The additive according to claim 4, wherein in S3, the organic solvent is an acid anhydride-based solvent;

and/or, in S3, the molar ratio of the 4-dimethylaminopyridine to the compound D1 is 0.0006-0.0012:1;

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 3-15 hours;

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

10. 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 1:38.5;

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 0.001:1;

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 6-10 hours;

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

11. The additive of claim 10, wherein in S2 the base participates in the reaction as an aqueous base.

12. The additive of claim 10, wherein in S2 the base is involved in the reaction in the form of an aqueous base, the mass ratio of base to water being 0.3:1.

13. The additive according to claim 4, wherein in S1, the temperature of the acetalization reaction is the reflux temperature of the solvent at normal temperature and normal pressure;

and/or, in S2, the base is potassium hydroxide;

and/or, in S2, the temperature of the ester hydrolysis reaction is the solvent reflux temperature at normal temperature and normal pressure;

And/or, in S3, the polymerization reaction is carried out at 130 ℃ for 6 hours and then at 190 ℃ for 10 hours.

14. 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 13.