WO2022027945A1

WO2022027945A1 - Fluorine-containing polymer for photoresist, top anti-reflection film composition comprising fluorine-containing polymer, and application of fluorine-containing polymer in photoresist

Info

Publication number: WO2022027945A1
Application number: PCT/CN2021/075376
Authority: WO
Inventors: 李永斌
Original assignee: 甘肃华隆芯材料科技有限公司
Priority date: 2020-08-04
Filing date: 2021-02-05
Publication date: 2022-02-10
Also published as: CN112034682A; CN112034682B; KR20220166818A

Abstract

The present invention relates to a fluorine-containing polymer for a photoresist, a top anti-reflection film composition comprising the fluorine-containing polymer, and an application of the fluorine-containing polymer in a photoresist. The structural formula of the fluorine-containing polymer for a photoresist is CF₂(CF₃)CF₂-[O-CF(CF₃)CF₂]n-O-CF(CF₃)COO-R, wherein n is in a range of 1-8, and R is one or more of H, NH₄, or other similar structures; based on the total weight of the polymer, the content a of a polymer component having a number average molecular weight less than 550 is 0-12%, the content b of a polymer component having a number average molecular weight of 650-900 is 75%-90%, the content c of a polymer component having a number average molecular weight of 980-1050 is 5%-15%, and the content d of a polymer component having a number average molecular weight greater than 1150 is 0-10%, wherein both a and d are 0, or either of a and d is 0, or neither of a and d is 0. According to the present invention, a fluorine-containing polymer meeting the specific constitution requirements in the present invention is obtained by controlling the content distribution of polymer components having different molecular weights in the fluorine-containing polymer; the fluorine-containing polymer is easy to degrade and environmentally friendly, has low toxicity, and can be used to prepare top anti-reflection films having a low refractive index.

Description

Fluoropolymer for photoresist, top anti-reflection film composition comprising the same, and application in photoresist

technical field

The present invention relates to the technical field of top anti-reflection films for photoresists, in particular to a fluorine-containing polymer for preparing top anti-reflection films, a composition for preparing top anti-reflection films containing the same, and the Top anti-reflection film for photoresist prepared from fluoropolymer or composition.

Background technique

Photolithography is a method of transferring semiconductor circuit patterns on a photomask to a silicon wafer. By irradiating the photomask with a laser or electron beam, the photosensitive substances on the wafer are changed in material properties due to exposure to light. , so as to complete the process of pattern transfer. The existing lithography technology is the most critical process unit in the manufacture of semiconductors, flat panel displays and other devices. However, there is a technical problem of light scattering in the existing photolithography process, which leads to low dimensional accuracy of photoresist imaging and inability to process patterns correctly. The current mainstream solution is to add a bottom anti-reflection film or a top anti-reflection film before and after photoresist coating. Among them, the main purpose of the top anti-reflection film is to reduce the interference of light in the photoresist and prevent the change of the lithography line width due to the change of the thickness of the photoresist. The top anti-reflection film is required to have low refractive index and high transmittance.

Known top antireflection films can be formed by applying a composition containing a fluorine-containing compound on the top surface of a photoresist. Fluorine-containing compounds have the characteristics of large molecular volume, small atomic refractive index, low refractive index, and the refractive index of fluorine-containing compounds is positively related to their own fluorine content. It can be developed in an aqueous solution system and can be removed together with the photoresist by a developing solution, which is very suitable for preparing a composition for forming a top reflective film. However, there are many types of fluorine-containing compounds known to be used, such as perfluorooctanoic acid, perfluorooctane sulfonic acid, and fluoropolymers.

Chinese patent application CN1666154A discloses an anti-reflection coating composition, which is mainly composed of an alkali-soluble fluoropolymer -[CF ₂ CF(OR _f COOH)]-(Rf represents a linear or branched perfluoroalkyl group, which may contain ether oxygen atoms), acids, amines and solvents. Chinese patent application CN101568991A discloses an anti-reflection film-forming composition comprising a specific naphthalene compound, a polymer (-[CF ₂ CF(OR _f COOH)]-) and a solvent. Japanese Patent Application JP09006008A discloses a water-soluble pattern-forming material using a fluoropolymer (F-[CF( _CF3 ) _CF2 -O] _p -CF( _CF3 )COOH, where p is 1- Integer of 10, but the surfactant cannot meet the conditions as an antireflection film. Japanese patent application JP10069091A discloses a composition for a top antireflection film comprising perfluoroalkyl ether carboxylic acid (F-[CF (CF ₃ )CF ₂ -O] _m -CF(CF ₃ )COOH, wherein m is an integer from 1 to 10, preferably an integer from 2 to 4), a homopolymer or copolymer of N-vinylpyrrolidone, and at least one An aqueous solution of amino acid derivatives. Taiwan patent application TW200928594A discloses a composition for a top anti-reflection film, which comprises the general formula Rf-O-[CF( _CF3 ) _CF2 -O] _m -CF( _CF3 )COOH fluorine-containing compounds (wherein Rf is a partially or perfluoro-substituted alkyl group, and m is an integer from 0 to 10), amine compounds and water-soluble polymers.

Although the fluoropolymers used for top anti-reflection films in the prior art can be used to form top anti-reflection films for lithography, they still have certain deficiencies in processability, film-forming properties, refractive index or raw material cost.

SUMMARY OF THE INVENTION

In view of the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a fluorine-containing polymer that can be used for preparing a top anti-reflection film for photoresist, and a fluorine-containing polymer containing the same for preparing a top anti-reflection film for photoresist Composition of reflective film, and top anti-reflective film for photoresist prepared therefrom. The fluoropolymer is easy to produce, low in raw material cost, low in toxicity, easily degradable, environmentally friendly, and the composition for preparing a top anti-reflection film comprising the fluoropolymer has good solution stability and film-forming property, and its pH The value can be matched with the pH value of the photoresist, and a top anti-reflection film with a lower refractive index can be prepared, thereby reducing the pattern defects that may be generated during the photolithography process and improving the quality of the photolithography pattern.

The object of the present invention is achieved through the following technical solutions:

A fluoropolymer for preparing a top anti-reflection film for photoresist, which has the following structure:

CF ₂ (CF ₃ )CF ₂ -[O-CF(CF ₃ )CF ₂ ] _n -O-CF(CF ₃ )COO-R

Wherein, R is one or more of H, NH ₄ or other similar structures; n is in the range of 1-8;

Based on the weight of the whole polymer, the content a of the polymer component with a number average molecular weight of less than 550 is 0-12%, and the content b of the polymer component with a number average molecular weight of 650-900 is 75-90%, the number average The content c of the polymer component with a molecular weight of 980-1050 is 5-15%, the content d of the polymer component with a number average molecular weight greater than 1150 is 0-10%, a and d are both 0 or either one is 0 or Also not 0.

After in-depth research, the inventors found that when the composition of the fluoropolymer described in the present application satisfies the above conditions, the composition solution for preparing the top anti-reflection film prepared by the fluoropolymer has good solution stability and good film-forming property, At the same time, the prepared top anti-reflection film has a refractive index of 1.41-1.44 at 248 nm, which can effectively reduce the refractive index under laser irradiation with a wavelength of 248 nm, and can be used as a top anti-reflection film for photoresist.

The inventors have found through intensive research that the composition of the fluoropolymer described in the present application has a significant impact on the stability and film-forming properties of the composition solution for preparing a top anti-reflection film containing it. When the content a is greater than 12%, the film-forming property of the composition prepared by the fluoropolymer is not good, and pores are likely to appear on the surface of the film; when the content d is greater than 10%, the composition prepared by the fluoropolymer is The stability of the material solution is not good, gels and agglomerates are likely to appear, and the film-forming properties of the composition are not good, the distribution of the formed film is not uniform, the surface of the film is prone to holes, and it is easy to be atomized; when the content of c is greater than 15% When the fluoropolymer is used, the solution stability of the composition prepared by the fluoropolymer is not good, gels and agglomerates are likely to appear, and the film-forming property of the composition is usually not good, the distribution of the formed film will be uneven, and the surface of the film is easy to be formed. Pores appear; when the content c is less than 5%, although the solution stability of the composition prepared by the fluoropolymer is good, and no gel and agglomerate appear, its film-forming property is usually not good, and the surface of the formed film is easy to appear Irregular patterns, tiny holes are formed, and the film surface is prone to fogging.

Further, the number average molecular weight of the fluoropolymer is between 600 and 1300, more preferably between 700 and 1100.

Further, the content b is 78-90%, preferably 80-90%. The content a is 0-10%, preferably 1-8%, more preferably 2-8%. The content c is 5-12%, preferably 5-10%. The content d is 0-8%, preferably 0-6%, more preferably 0-4%.

The fluorine-containing polymer can be polymerized by photo-oxidation, catalytic oligomerization, plasma or anion polymerization, and then react with water, amine, ester or similar compounds to form corresponding carboxylic acid groups, Amine-based, ester-based or other fluoropolymers of similar structure.

The present invention also provides a composition for preparing a top anti-reflection film for photoresist, which comprises any one of the aforementioned fluoropolymers of the present invention.

Further, the composition for preparing the top anti-reflection film contains 1-15%, preferably 2-12%, more preferably 2-8% of the fluoropolymer by weight.

Further, the composition for preparing the top anti-reflection film further comprises a water-soluble resin, and the molar ratio of the fluoropolymer to the water-soluble resin is 1:2-1:30, preferably 1:3-1:25.

The water-soluble resin can be one or more of polyvinylpyrrolidone, polyacrylic acid and polyurethane, or a water-soluble resin obtained by substituting fluorine atoms for all or part of the hydrogen atoms of the alkyl groups of the above-mentioned water-soluble resins. resin. The number average molecular weight of the water-soluble resin is 3000-30000, preferably 4000-26000, more preferably 6000-22000.

The polyvinylpyrrolidone can be polyvinylpyrrolidone, or it can be a polymer of polyvinylpyrrolidone and other monomers. The polyvinylpyrrolidone can be used alone or in combination.

The polyacrylic acid can be polyacrylic acid, or it can be a polymer of polyacrylic acid and other monomers, and the polyacrylic acid can be used alone or in combination.

The polyurethanes refer to polyurethanes, and can also be polymers of polyurethanes and other monomers. Polyurethanes can be used alone or in combination.

Further, the composition for preparing the top anti-reflection film further comprises amine, and the content of the amine may be 0.2wt%-2wt%, preferably 0.3-1wt%. The amine can be one or more of ammonia water, tetramethylammonium hydroxide, alkanolamine, aromatic amine, alkylamine and other structures, preferably tetramethylammonium hydroxide.

The composition for preparing the top anti-reflection film also contains water and/or a water-soluble organic solvent, and the water-soluble organic solvent can be alcohols, ketones or esters; preferably the water-soluble organic solvent is methanol, ethanol, Isopropanol, acetone, methyl acetate, ethyl acetate, ethyl lactate, dimethylformamide or dimethyl sulfoxide.

The present invention also provides the application of any of the aforementioned fluoropolymers of the present invention for preparing a top anti-reflection film for photoresist. The present invention also provides a top anti-reflection film for photoresist, which is prepared from a raw material comprising any one of the aforementioned fluoropolymers or any one of the compositions of the present invention.

The beneficial effects of the present invention are as follows:

In the present invention, by controlling the content distribution of polymer components with different molecular weights in the fluoropolymer, a fluoropolymer meeting the specific composition requirements of the present invention is obtained. The fluoropolymer is easy to degrade, has low toxicity, and is environmentally friendly. The composition solution used for preparing the top anti-reflection film has good solution stability and film-forming properties, and the anti-reflection film prepared by it has a refractive index of 1.41-1.44 under a 248nm light source, and the pH of the composition is consistent with the photoresist. It has good pH matching and can be used as a top anti-reflection film for photoresist to reduce the standing wave effect in the photolithography process and improve the yield of the photolithography process.

Description of drawings

Figures 1a-1f are photos of the solution state of the composition solution prepared by the perfluoropolyether carboxylic acid of Examples 1-6 of the present application after standing for 14 days, Figures 1a, 1b, 1c, 1d, 1e and 1f correspond to Example 1, respectively -6;

Figures 2a-2c are photos of the composition solution prepared by the perfluoropolyether carboxylic acid of Comparative Example 2, and Figures 2a, 2b and 2c are photos of the 3rd, 7th and 14th days of standing, respectively;

Figures 3a-3c are photos of the composition solution prepared by the perfluoropolyether carboxylic acid of Comparative Example 3, and Figures 3a, 3b and 3c are photos of the 3rd, 7th and 14th days of standing, respectively;

Figures 4a-4f and Figures 4a'-4f' are photographs of the films formed by the compositions prepared from the perfluoropolyether carboxylic acids of Examples 1-6 of the present application, Figures 4a, 4b, 4c, 4d, 4e and 4f correspond respectively Macrophotographs of Examples 1-6, Figures 4a', 4b', 4c', 4d', 4e' and 4f' correspond to the microphotographs of Examples 1-6 respectively;

Figures 5a-5d and Figures 5a'-5d' are photographs of films formed by the compositions prepared from the perfluoropolyether carboxylic acid of Comparative Examples 1-4 of the present application, and Figures 5a, 5b, 5c and 5d correspond to Comparative Examples 1- Macrophotographs of 4, Figures 5a', 5b', 5c' and 5d' are microphotographs of Comparative Examples 1-4.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Preparation of perfluoropolyether carboxylic acid:

First, 50ml of acetonitrile and 50ml of tetraethylene glycol dimethyl ether were added to the 1L polymerization kettle, and then 5g of catalyst KF was added to the polymerization kettle. After stirring and mixing evenly, it was replaced with high-purity nitrogen three times, and the negative pressure was pumped to -0.1MPa. , cooled to the set temperature of 0 ° C, and introduced 50 g of hexafluoropropylene oxide. Timing feeding (50g/h) was adopted, the reaction process was controlled, and the temperature was controlled between 0 and 10°C. After adding hexafluoropropylene oxide to 1000 g, return to normal pressure, and after the reaction is completed, keep stirring for two hours, stop stirring, and return to room temperature to obtain a mixture.

The mixture is separated into layers, the reaction product in the lower layer is centrifuged and filtered to separate out the reaction product, and the reaction product is added to the distillation apparatus. Purified by rectification to obtain perfluoropolyether acyl fluoride with a purity of more than 99% (purity measured by gas chromatography).

Add the perfluoropolyether acyl fluoride to a 1L transfer acid kettle, add water according to the volume ratio of perfluoropolyether acyl fluoride and water 1:3, heat to reflux for four hours, and continue to heat up to 90 ° C for demulsification. After that, it was left to stand for liquid separation to remove the water in the upper part. After repeating the above steps twice, the temperature was raised to 110° C. to remove residual water and hydrogen fluoride to obtain perfluoropolyether carboxylic acid.

By controlling the molecular weight of perfluoropolyether acyl fluoride, the following perfluoropolyether carboxylic acids with different molecular weights were obtained:

Perfluoropolyether carboxylic acid A with a number average molecular weight of 489, perfluoropolyether carboxylic acid B with a number average molecular weight of 715, perfluoropolyether carboxylic acid C with a number average molecular weight of 808, and perfluoropolyether carboxylic acid with a number average molecular weight of 994 Polyether carboxylic acid D, perfluoropolyether carboxylic acid E with a number average molecular weight of 1160, and perfluoropolyether carboxylic acid F with a number average molecular weight of 1567.

Example 1:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 10% perfluoropolyether carboxylic acid A, 80% perfluoropolyether carboxylic acid B, 6% perfluoropolyether Carboxylic acid D, 4% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Example 2:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 5% perfluoropolyether carboxylic acid A, 85% perfluoropolyether carboxylic acid B, 8% perfluoropolyether Carboxylic acid D, 2% perfluoropolyether carboxylic acid F. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Example 3:

The above perfluoropolyether carboxylic acids with different molecular weights are mixed, and the mixing ratio is as follows: by weight, 7% perfluoropolyether carboxylic acid A, 78% perfluoropolyether carboxylic acid C, 9% perfluoropolyether Carboxylic acid D, 6% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Example 4:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 0% perfluoropolyether carboxylic acid A, 84% perfluoropolyether carboxylic acid C, 13% perfluoropolyether Carboxylic acid D, 3% perfluoropolyether carboxylic acid F. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Example 5:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 3% perfluoropolyether carboxylic acid A, 89% perfluoropolyether carboxylic acid B, 7% perfluoropolyether Carboxylic acid D, 1% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Example 6:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 6% perfluoropolyether carboxylic acid A, 86% perfluoropolyether carboxylic acid C, 8% perfluoropolyether Carboxylic acid D, 0% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Comparative Example 1:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 14% perfluoropolyether carboxylic acid A, 79% perfluoropolyether carboxylic acid B, 6% perfluoropolyether Carboxylic acid D, 1% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Comparative Example 2:

The above perfluoropolyether carboxylic acids of different molecular weights are mixed, and the mixing ratio is as follows: by weight, 3% perfluoropolyether carboxylic acid A, 79% perfluoropolyether carboxylic acid B, 6% perfluoropolyether Carboxylic acid D, 12% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Comparative Example 3:

The above perfluoropolyether carboxylic acids with different molecular weights are mixed, and the mixing ratio is as follows: by weight, 2% perfluoropolyether carboxylic acid A, 78% perfluoropolyether carboxylic acid B, 17% perfluoropolyether Carboxylic acid D, 3% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

Comparative Example 4:

When preparing perfluoropolyether carboxylic acid, each polymer is mixed, and the mixing ratio is as follows: 10% perfluoropolyether carboxylic acid A, 82% perfluoropolyether carboxylic acid B, 4% perfluoropolyether carboxylic acid B by weight Fluoropolyether carboxylic acid D, 4% perfluoropolyether carboxylic acid E. Thus, a perfluoropolyether carboxylic acid was prepared, the specific composition of which is shown in Table 1.

The number-average molecular weight of perfluoropolyether carboxylic acid was measured by acid number method, as follows:

Pipette 1ml of perfluoropolyether carboxylic acid to be tested, weigh and record the data m(g), add 35ml of water and 15ml of absolute ethanol, titrate with sodium hydroxide solution of standard concentration c (mol/ml), and titrate to pH When =7, record the volume v (ml) of sodium hydroxide consumed. Calculate the number average molecular weight of perfluoropolyether carboxylic acid according to the following formula:

Number average molecular weight of perfluoropolyether carboxylic acid = m/cv

Formulation of compositions for making top antireflection films

Using the perfluoropolyether carboxylic acids of Examples 1-6 and Comparative Examples 1-4, the compositions for top antireflective films were formulated by the following steps:

0.016 moles of perfluoropolyether carboxylic acid is prepared into a 5 mass % aqueous solution, and then mixed with a 5 mass % polyvinylpyrrolidone aqueous solution at a molar ratio of perfluoropolyether carboxylic acid and polyvinylpyrrolidone of 1:10, and stirring until A clear solution was obtained using polyvinylpyrrolidone from Aladdin

Polyvinylpyrrolidone K16-18; under stirring condition, add 5 mass % tetramethylammonium hydroxide solution to the solution, the molar ratio of tetramethylammonium hydroxide to perfluoropolyether carboxylic acid is 0.9:1 ; Then, add oxalic acid to adjust the pH value to 2.0-2.5; filter to obtain the composition solution.

The solution stability, film-forming property, and refractive index of each of the prepared compositions were evaluated by the following methods, and the results are shown in Table 1.

250ml of the obtained composition solution for preparing anti-reflection film was placed in a 500ml beaker, left standing, and the condition of the solution was visually observed, and the time at which the precipitated flocs appeared was recorded as the stable time h (in days). ), to evaluate its stability, and 14 days was the cut-off time for observation. The larger the h value, the better the solution stability.

<Film-forming property evaluation method>

Use a spin coater (Laurell, USA, model: WS-650MZ-23NPPB) to coat silicon wafers (4 inches, supplier TOPVENDOR, model P, doped with boron, about 525 μm in thickness, about 100 mm in diameter) for each A composition solution for preparing an anti-reflection film was baked at 100° C. for 90 seconds, and after cooling down, a corresponding film was formed. The condition of the formed film was visually observed, and the microscopic observation was carried out with the aid of a metallographic microscope (Chongqing Aote Optical Instrument Co., Ltd. MIT500) to evaluate the film-forming property of the composition, and macroscopic and microscopic photos were taken by a digital camera and a metallographic microscope, respectively. .

On a silicon wafer (4 inches, supplier TOPVENDOR, type P, doped with boron, thickness about 525 μm, diameter about 100 mm), use a spin coater (Laurell, USA, model: WS-650MZ-23NPPB) to coat each for The composition solution of the anti-reflection film was prepared, baked at 100° C. for 90 seconds, and after the temperature was lowered, a coating film was formed. Using the Wallon RC2 ellipsometer to measure the refractive index at 248nm.

Table 1

Note: 1) The percentages in the table are by weight, and the number-average molecular weight refers to the number-average molecular weight of perfluoropolyether carboxylic acid;

2) Contents a, b, c, and d are respectively as defined in this application, for example, content a is the content of polymer components with a number average molecular weight of less than 550.

It can be seen from Table 1 and Figure 1 that the composition solutions prepared by the perfluoropolyether carboxylic acid of Examples 1-6 that meet the requirements of the component content of the present application are left standing for 14 days, and still remain clear, and no precipitated flocs appear. , has good solution stability. In addition, it can be seen from Table 1 and Figure 4 that the compositions prepared from the perfluoropolyether carboxylic acids of Examples 1-6 of the present application can form a film with a uniform surface, have good film-forming properties, and at the same time, the prepared anti-reflection The refractive index of the film at 248 nm is 1.41-1.44, which can effectively reduce the refractive index under laser irradiation with a wavelength of 248 nm, and can be used as a top anti-reflection film for photoresist.

As can be seen from Table 1 and Figure 5, since the perfluoropolyether carboxylic acid of Comparative Example 1 contains 14% of the polymer component with a number average molecular weight of less than 550, the film-forming property of the prepared composition is not good. The formed film has obvious pores.

As can be seen from Table 1, Figure 2 and Figure 5, since the perfluoropolyether carboxylic acid of Comparative Example 2 contains 12% of polymer components with a number average molecular weight greater than 1150, the solution stability of the prepared composition is not stable. Well, gels and agglomerates appeared on the 3rd day of standing, and until the 14th day of standing, there were still obvious gels and agglomerates in the solution; The film was unevenly distributed and had obvious pores, and the film was prone to fogging.

As can be seen from Table 1, Figure 3 and Figure 5, since the perfluoropolyether carboxylic acid of Comparative Example 3 contains 17% of a polymer component with a number average molecular weight of 980-1050, the prepared composition solution is stable The property is not good, gels and agglomerates appear on the 3rd day of standing, and until the 14th day of standing, there are still obvious gels and agglomerates in the solution; the film-forming property of the prepared composition is very poor , the formed film distribution is obviously non-uniform and has pores.

As can be seen from Table 1 and Figure 5, since the perfluoropolyether carboxylic acid of Comparative Example 4 only contains 4% of the polymer component with a number average molecular weight of 980-1050, although the prepared composition has good solution stability , it still remained clear on the 14th day, but the film-forming properties of the prepared composition were very poor, there were many needle-like radial patterns on the surface of the film, there were many agglomeration points and tiny holes, and the film was easy to Fogging, fogging occurs within a day.

It can be seen that the composition solution prepared according to the perfluoropolyether carboxylic acid that meets the requirements of the component content of the present application has good solution stability and good film-forming property, and the refractive index of the anti-reflection film prepared by it at 248 nm is at the same time. It is 1.41-1.44, which can effectively reduce the refractive index under laser irradiation with a wavelength of 248 nm, and can be used as a top anti-reflection film for photoresist. Compositions prepared from perfluoropolyether carboxylic acids that do not meet the component content requirements of the present application have problems of poor solution stability and/or film-forming properties, which in turn makes it difficult to use as a top anti-reflection film for photoresists.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should Various changes may be made in details without departing from the scope of the invention as defined by the claims.

Claims

A fluorine-containing polymer for preparing a top anti-reflection film for photoresist, characterized in that its structural formula is as follows:

CF 2 (CF 3 )CF 2 -[O-CF(CF 3 )CF 2 ] n -O-CF(CF 3 )COO-R

Wherein, n is in the range of 1-8, and R is one or more of H, NH 4 or other similar structures;

Based on the weight of the whole polymer, the content a of the polymer component with a number average molecular weight of less than 550 is 0-12%; the content b of the polymer component with a number average molecular weight of 650-900 is 75%-90%; The content c of the polymer component with an average molecular weight of 980-1050 is 5%-15%; the content d of the polymer component with a number average molecular weight greater than 1150 is 0-10%, and a and d are both 0 or any one of 0 or both.
The fluoropolymer for preparing a top anti-reflection film for photoresist according to claim 1, wherein the number average molecular weight of the fluoropolymer is between 600 and 1300, more preferably between 700 and 700. between 1100.
The fluoropolymer for preparing a top anti-reflection film for photoresist according to claim 1 or 2, wherein the content b is 78-90%, preferably 80-90%.
The fluoropolymer for preparing a top anti-reflection film for photoresist according to any one of the preceding claims, wherein the content a is 0-10%, preferably 1-8%, more preferably 2 -8%.
The fluoropolymer for preparing a top anti-reflection film for photoresist according to any one of the preceding claims, characterized in that the content c is 5-12%, preferably 5-10%.
The fluoropolymer for preparing a top anti-reflection film for photoresist according to any one of the preceding claims, wherein the content d is 0-8%, preferably 0-6%, more preferably 0 -4%.
A composition for preparing a top anti-reflection film for photoresist, characterized in that it comprises the fluoropolymer described in any one of claims 1-6.
The composition for preparing a top anti-reflection film for photoresist according to claim 7, characterized in that it contains 1-15%, preferably 2-12% by weight of the fluoropolymer.
The composition for preparing a top anti-reflection film for photoresist according to claim 7 or 8, further comprising a water-soluble resin, and the molar ratio of the fluoropolymer to the water-soluble resin is 1:2 to 1:30, preferably 1:3 to 1:25.
A top anti-reflection film for photoresist, which is prepared from a raw material comprising the fluoropolymer of any one of claims 1-6 or the composition of any one of claims 7-9.