Polymer as well as preparation method and application thereof

Abstract

The invention discloses a polymer as well as a preparation method and application thereof. The polymers of the invention are prepared by the following method; the preparation method of the polymer comprises the following steps: in the presence of an initiator, carrying out polymerization reaction on a monomer as shown in a formula A and a monomer as shown in a formula B in an organic solvent to obtain the polymer, in parts by weight, the monomer A accounts for 1 to 15 parts; and the weight part of the monomer B is 1-10. The polymer disclosed by the invention is applied to ArF immersion photoetching, so that the problems that the performance of photoresist is reduced and the defects are increased can be reduced. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a polymer, a preparation method thereof and an application thereof. Background Art

[0002] In recent years, due to the continuous high integration of large scale integrated circuits (LSIs), for the miniaturization of the lithography process, especially for the ultra-fine pattern process below the 30 nm node, the resolution of the photoresist used in the lithography process has become a decisive important factor. Therefore, in the commonly used g-line or i-line regions, the wavelength of the exposure light has also been further shortened, and thus the research on lithography using deep ultraviolet light, KrF excimer laser, and ArF excimer laser has attracted much attention.

[0003] After processes such as coating, baking, exposure, development, and etching, the fine pattern on the mask can be transferred to the substrate. The shorter the exposure wavelength, the higher the resolution of the photoresist. In recent years, as the semiconductor manufacturing process has gradually improved, ArF immersion lithography has become the dominant lithography process for advanced processes. ArF immersion lithography continues the ArF light source, adds a water medium between the photoresist and the lithography machine lens, increases the numerical aperture (NA) of the lithography machine, shortens the wavelength irradiated on the photoresist, and improves the resolution and depth of focus of the photoresist.

[0004] However, component exchange occurs between the photoresist and water, resulting in contamination and damage of the water and the lithography machine lens, a decrease in the performance of the photoresist, and an increase in defects. Increasing the hydrophobicity of the photoresist film-forming resin and the activation energy of the protecting group can inhibit the leaching of small molecules, but the effect is limited. Therefore, it is necessary to consider forming a water-resistant coating on the surface of the photoresist. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the decrease in the performance of the photoresist and the increase in defects in ArF immersion lithography, and provide a polymer, a preparation method thereof and an application thereof. The top coating film containing the polymer of the present invention has any one of the following advantages: better alkali solubility, good hydrophobicity, higher sliding angle, higher receding contact angle, and faster dissolution rate. In addition, the double-layer resin film containing the polymer of the present invention has strong stability and excellent pattern resolution.

[0006] The present invention provides a polymer, which is prepared by the following method; the preparation method of the polymer includes the following steps: in the presence of an initiator, polymerize the monomer shown in formula A and the monomer shown in formula B in an organic solvent to obtain the polymer;

[0007] By weight, the weight of monomer A is 1-15 parts; the weight of monomer B is 1-10 parts;

[0008]

[0009] n is an integer from 1 to 10.

[0010] In a certain embodiment of the present invention, in the polymer, based on parts by weight, the weight parts of the monomer represented by Formula A are 2 - 10 parts, preferably 2 parts, 4 parts, 5 parts, 8 parts or 10 parts.

[0011] In a certain embodiment of the present invention, in the polymer, based on parts by weight, the weight parts of the monomer represented by Formula B are 1 - 6 parts, preferably 1 part, 1.5 parts, 2 parts, 3.5 parts or 6 parts.

[0012] In a certain embodiment of the present invention, in the polymer, the initiator is preferably an azo initiator, such as azobisisobutyronitrile.

[0013] In a certain embodiment of the present invention, in the polymer, based on parts by weight, the weight parts of the initiator are 0.05 - 0.3 parts, preferably 0.1 part.

[0014] In a certain embodiment of the present invention, in the polymer, the organic solvent is a ketone solvent, preferably selected from one or more of methyl ethyl ketone, N - methylpyrrolidone and cyclohexanone, preferably methyl ethyl ketone.

[0015] In a certain embodiment of the present invention, in the polymer, based on parts by weight, the weight parts of the organic solvent are 10 - 20 parts, preferably 15 parts.

[0016] In a certain embodiment of the present invention, the weight - average molecular weight (Mw) of the polymer is 5000 - 13000, such as 5700 - 12200.

[0017] In a certain embodiment of the present invention, in the monomer represented by Formula B in the polymer, n is 3.

[0018] In a certain embodiment of the present invention, in the preparation method of the polymer, the temperature of the polymerization reaction is 60 - 100 °C, such as 70 °C.

[0019] In a certain embodiment of the present invention, in the preparation method of the polymer, the time of the polymerization reaction is 10 - 24 hours, such as 12 hours.

[0020] In a certain embodiment of the present invention, the raw materials for the polymerization reaction are the monomer represented by Formula A, the monomer represented by Formula B, the initiator and the organic solvent.

[0021] In a certain embodiment of the present invention, in the preparation method of the polymer, after the polymerization reaction, there are also post - treatment steps, such as cooling, precipitation and drying.

[0022] Among them, the solvent used in the precipitation is preferably an alkane solvent, such as n - hexane.

[0023] Among them, the amount of the solvent used in the precipitation is conventional in this type of reaction in the art. The weight ratio of the n - hexane to the organic solvent can be (3 - 4):1, preferably 3.3:1.

[0024] Among them, the drying can be vacuum drying, such as vacuum drying at 50 °C for 24 hours.

[0025] In a certain embodiment of the present invention, in the method for preparing the polymer, the polymerization reaction can be carried out under an inert gas (such as nitrogen).

[0026] In a certain embodiment of the present invention, the polymer is any one of the following polymers:

[0027] Polymer P1: By weight, the weight fraction of the monomer shown by formula A is 2 parts, the weight fraction of the monomer shown by formula B is 1 part, the weight fraction of methyl ethyl ketone is 15 parts, and the weight fraction of azobisisobutyronitrile is 0.1 part; the weight - average molecular weight can be 5784;

[0028] Polymer P2: By weight, the weight fraction of the monomer shown by formula A is 4 parts, the weight fraction of the monomer shown by formula B is 1.5 parts, the weight fraction of methyl ethyl ketone is 15 parts, and the weight fraction of azobisisobutyronitrile is 0.1 part; the weight - average molecular weight can be 7851;

[0029] Polymer P3: By weight, the weight fraction of the monomer shown by formula A is 5 parts, the weight fraction of the monomer shown by formula B is 2 parts, the weight fraction of methyl ethyl ketone is 15 parts, and the weight fraction of azobisisobutyronitrile is 0.1 part; the weight - average molecular weight can be 8938;

[0030] Polymer P4: By weight, the weight fraction of the monomer shown by formula A is 8 parts, the weight fraction of the monomer shown by formula B is 3.5 parts, the weight fraction of methyl ethyl ketone is 15 parts, and the weight fraction of azobisisobutyronitrile is 0.1 part; the weight - average molecular weight can be 10089;

[0031] Polymer P5: By weight, the weight fraction of the monomer shown by formula A is 10 parts, the weight fraction of the monomer shown by formula B is 6 parts, the weight fraction of methyl ethyl ketone is 15 parts, and the weight fraction of azobisisobutyronitrile is 0.1 part; the weight - average molecular weight can be 12157;

[0032] Among polymers P1 to P5, monomer B is

[0033] The present invention also provides a method for preparing the above polymer, which comprises the following steps: in the presence of an initiator, polymerizing the monomer represented by formula A and the monomer represented by formula B in an organic solvent to obtain the polymer;

[0034] By weight, the weight parts of monomer A are 1-15 parts; the weight parts of monomer B are 1-10 parts;

[0035]

[0036] n is an integer from 1 to 10.

[0037] The operations and conditions of the polymerization reaction are the same as those described above.

[0038] The present invention also provides a top coating liquid, which comprises the following components by mass fraction: 1-5% of the above polymer and 95-99% of an organic solvent; % is the mass fraction percentage of each component in the total mass of the top coating liquid.

[0039] In a certain embodiment of the present invention, in the top coating liquid, the organic solvent is an alcohol solvent, preferably 4-methyl-2-pentanol.

[0040] In a certain embodiment of the present invention, in the top coating liquid, the mass fraction of the polymer is 2-3%, for example 3%.

[0041] In a certain embodiment of the present invention, in the top coating liquid, the mass fraction of the organic solvent is 96-99%, for example 97%.

[0042] In a certain embodiment of the present invention, the top coating liquid consists of the above polymer and the above organic solvent, and the types and mass fractions of the polymer and the organic solvent are the same as those described above.

[0043] The present invention also provides a top coating film, which comprises the above polymer.

[0044] In a certain embodiment of the present invention, the top coating film is prepared by the following method; the preparation method of the top coating film comprises the following steps: coating the above top coating liquid on the surface of a silicon wafer and drying it.

[0045] In a certain embodiment of the present invention, in the top coating film, before coating, the top coating liquid is preferably filtered using a membrane filter; more preferably, the pore size of the membrane filter is 0.2 μm.

[0046] In a certain embodiment of the present invention, in the top coating film, the drying temperature can be 50-120 °C, preferably 80 °C.

[0047] In a certain embodiment of the present invention, in the top coating film, the drying time is 70 - 180 seconds, preferably 90 seconds.

[0048] In a certain embodiment of the present invention, in the top coating film, the coating method can be a conventional coating method in the art, such as spin coating.

[0049] In a certain embodiment of the present invention, in the top coating film, the spin coating is conventional in the art, and preferably a spinner with a rotation speed of 1400 - 1600 rpm (such as 1500 rpm) is used.

[0050] The present invention also provides a method for preparing the above-mentioned top coating film, which includes the following steps: coating the above-mentioned top coating liquid on the surface of a silicon wafer.

[0051] The conditions and operations of the method for preparing the top coating film are the same as those described above.

[0052] The present invention also provides a double-layer resin film, which includes a resist layer and a top coating film layer coated on the resist layer.

[0053] In a certain embodiment of the present invention, the resist layer is a layer formed in a tai-6990PH (such as the photoresist manufactured by TOK) photoresist.

[0054] In a certain embodiment of the present invention, the thickness of the double-layer resin film is 175 - 225 nm, such as 200 nm.

[0055] In a certain embodiment of the present invention, the thickness of the top coating film layer is 35 - 60 nm, such as 50 nm.

[0056] In a certain embodiment of the present invention, the thickness of the resist layer is 140 - 165 nm, such as 150 nm.

[0057] In a certain embodiment of the present invention, the double-layer resin film is composed of a resist layer as described above and a top coating film layer coated on the resist layer as described above.

[0058] The present invention also provides a method for preparing the above-mentioned double-layer resin film, which includes the following steps: coating a resist solution on the surface of a substrate (silicon wafer) to obtain a resist layer; coating a top coating liquid on the resist layer to obtain the double-layer resin film.

[0059] The resist layer is a conventional resist layer in the art, and its preparation method preferably includes the following steps: coating a resist solution on the surface of a silicon wafer and drying.

[0060] In a certain embodiment of the present invention, in the method for preparing the double-layer resin film, in the method for preparing the resist layer, the coating is conventional in this type of reaction in the art, and preferably spin coating.

[0061] In one embodiment of the present invention, in the preparation method of the double-layer resin film, the top coating liquid is preferably filtered using a membrane filter. More preferably, the pore size of the membrane filter is 0.2 μm.

[0062] In one embodiment of the present invention, in the preparation method of the double-layer resin film, the drying temperature is preferably 70 - 120 °C, such as 80 °C or 100 °C.

[0063] In one embodiment of the present invention, in the preparation method of the double-layer resin film, the drying time is preferably 80 - 120 seconds, such as 90 seconds.

[0064] The present invention also provides an application of the above polymer, the above top coating film or the above double-layer resin film in ArF immersion lithography.

[0065] On the basis of conforming to common general knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0066] The reagents and raw materials used in the present invention are all commercially available. Among them, monomers A and B are both purchased from Suzhou Meiming Electronic Technology Co., Ltd.

[0067] The positive and progressive effects of the present invention are as follows: The top coating film containing the polymer of the present invention is insoluble in water but easily soluble in a photoresist developer (especially an alkaline developer), and does not interact with the photoresist. It has at least the following advantages: better alkali solubility and hydrophobicity, a higher sliding angle, a higher receding contact angle, and a faster dissolution rate. In addition, the double-layer resin film containing the polymer of the present invention has the advantages of strong stability and excellent pattern resolution. Specific Embodiments

[0068] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the examples described herein. For the experimental methods without specific conditions noted in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0069] Preparation Method:

[0070] Replace the air in the glass flask with nitrogen to make the atmosphere in the flask nitrogen. Then, add the components in Table 1 to the glass flask equipped with a condenser in sequence. Heat the reaction solution to 70 °C and stir for 12 hours. After the reaction is terminated, pour it into 50 g of n-hexane and stir. Take out the generated precipitate. Dry it at 50 °C for 24 hours to form a white solid, obtaining the polymer. The molecular weight is calculated by gel permeation chromatography (GPC, standard substance: polystyrene).

[0071]

[0072] Table 1 Components in the Polymer

[0073] Polymer Monomer A Monomer B Methyl ethyl ketone Azobisisobutyronitrile <![CDATA[M W > P1 2g 1g 15g 0.1g 5784 P2 4g 1.5g 15g 0.1g 7851 P3 5g 2g 15g 0.1g 8938 P4 8g 3.5g 15g 0.1g 10089 P5 10g 6g 15g 0.1g 12157

[0074] Preparation of the Top Coating Solution

[0075] 100 g of the synthesized polymer was dissolved in 900 g of the solvent 4-methyl-2-pentanol (MIBC), and then the concentration of the polymer was adjusted to 3 wt% with 2300 g of 4-methyl-2-pentanol to obtain a uniform and transparent top coating solution.

[0076] Fabrication of the Top Coating Film

[0077] Each top coating solution was filtered through a membrane filter (0.2 μm), and then spin-coated onto a silicon wafer at a rotation speed of 1500 rpm using a spinner, and dried on a hot plate at 80 °C for 90 seconds to obtain a uniform top coating film of about 50 nm on the silicon wafer.

[0078] Advancing Contact Angle / Receding Contact Angle Evaluation Test

[0079] For the top coating film and the single-layer resist film formed on the silicon wafer, the advancing contact angle and receding contact angle of water droplets were measured at 20 °C by the expansion / contraction method using a CA-X type device manufactured by Kyowa Surface Science.

[0080] Alkaline Developer Solubility Test

[0081] For the top coating film and the single-layer resist film formed on the silicon wafer, the dissolution rate in a 2.38% aqueous solution of tetramethylammonium hydroxide (alkaline developer) was measured at 20 °C using a resist developer analyzer RDA-790 (manufactured by Litho Tech Japan Corporation).

[0082] Fabrication of the Resist / Top Coating Double-Layer Resin Film

[0083] A resist solution (the photoresist is tai-6990PH manufactured by TOK, and the photoacid generator (PAG) is triphenylsulfonium trifluoromethanesulfonate manufactured by Midori Kagaku Co., Ltd.) was spin-coated onto a silicon wafer using a spinner, and then dried on a hot plate at 100 °C for 90 seconds to form a resist film with a film thickness of about 150 nm. The top coating solution filtered through a membrane filter (0.2 μm) was spin-coated onto this resist film using a spinner, and then dried on a hot plate at 80 °C for 90 seconds to form a double-layer resin film with an overall film thickness of about 200 nm (a double-layer film composed of a resist layer and a top coating).

[0084] For the double-layer resin film formed on the silicon wafer, the following pure water immersion treatment and exposure imaging test were carried out.

[0085] Pure water immersion test

[0086] The five silicon wafers having a double-layer resin film (a double-layer film consisting of a resist layer and a top coat layer) and the silicon wafer having a single-layer resist film were immersed in 20 ml of pure water at 20° C. for 10 minutes, respectively. After extracting the eluted matter, the extract was measured by ion chromatography to confirm the presence of triphenylsulfonium trifluoromethanesulfonate in the eluted matter.

[0087] Exposure resolution (patterning) test

[0088] A double-layer resin film (a double-layer film consisting of a resist layer and a top coating) silicon wafer and a single-layer resist film silicon wafer formed by pre-baking at 80°C for 90 seconds were exposed at 193nm through a photomask. Pure water was dripped for 2 minutes while rotating the exposed wafer. Then, the exposure was post-baked at 120°C for 60 seconds and developed with an alkaline developer. A 2.38% tetramethylammonium hydroxide aqueous solution was used as an alkaline developer. The cross-section of the obtained pattern was observed using a scanning electron microscope, and the pattern resolution was characterized by the degree of deformation of the rectangle.

[0089] Table 2 Evaluation test of top coating film

[0090]

[0091] Table 3 Evaluation test of double-layer resin film

[0092] Double-layer resin film Pure water immersion experiment Pattern resolution Double-layer resin film 1 No eluted triphenylsulfonium trifluoromethanesulfonate detected Rectangle Double-layer resin film 2 No eluted triphenylsulfonium trifluoromethanesulfonate detected Rectangle Double-layer resin film 3 No eluted triphenylsulfonium trifluoromethanesulfonate detected Rectangle Double-layer resin film 4 No eluted triphenylsulfonium trifluoromethanesulfonate detected Rectangle Double-layer resin film 5 No eluted triphenylsulfonium trifluoromethanesulfonate detected Rectangle Single-layer resist film Eluted triphenylsulfonium trifluoromethanesulfonate detected Swelling and deformation

[0093] Conclusion: The top coating film prepared by using polymers P1-P5 has a higher sliding angle, a higher receding contact angle and a faster dissolution rate. It can be seen that the top coating film prepared by using polymers P1-P5 of the present invention has better alkali solubility and hydrophobicity. In addition, the obtained double-layer resin film has strong stability and excellent graphic resolution. The double-layer resin film of the present invention was immersed in pure water, and no peak belonging to triphenylsulfonium trifluoromethanesulfonate or its decomposition product was detected. It can be seen that by setting the top coating, the dissolution of the photoacid generator of the resist component in water is suppressed.

Claims

1. A polymer, characterized in that, It is prepared by the following method; the preparation method of the polymer comprises the following steps: in the presence of an initiator, polymerize the monomer shown in formula A and the monomer shown in formula B in an organic solvent to obtain the polymer; By weight, the weight parts of monomer A are 1-15 parts; the weight parts of monomer B are 1-10 parts; n is an integer from 1 to 10.

2. The polymer according to claim 1, wherein It satisfies one or more of the following conditions; (1) In the polymer, by weight, the weight parts of the monomer shown in formula A are 2-10 parts; (2) In the polymer, by weight, the weight parts of the monomer shown in formula B are 1-6 parts; (3) In the polymer, the initiator is an azo initiator; (4) In the polymer, by weight, the weight parts of the initiator are 0.05-0.3 parts; (5) In the polymer, the organic solvent is a ketone solvent; (6) In the polymer, by weight, the weight parts of the organic solvent are 10-20 parts; (7) In the polymer, the weight-average molecular weight of the polymer is 5000-13000; (8) In the polymer, in the monomer shown in formula B, n is 3.

3. The polymer according to claim 2, wherein It satisfies one or more of the following conditions; (1) In the polymer, by weight, the weight parts of the monomer shown in formula A are 2 parts, 4 parts, 5 parts, 8 parts or 10 parts; (2) In the polymer, by weight, the weight parts of the monomer shown in formula B are 1 part, 1.5 parts, 2 parts, 3.5 parts or 6 parts; (3) In the polymer, the initiator is azobisisobutyronitrile; (4) In the polymer, by weight, the weight parts of the initiator are 0.1 part; (5) In the polymer, the organic solvent is selected from one or more of methyl ethyl ketone, N-methylpyrrolidone and cyclohexanone; (6) In the polymer, by weight, the weight parts of the organic solvent are 15 parts; (7) In the polymer, the weight-average molecular weight of the polymer is 5700-12200.

4. The polymer according to claim 3, wherein In the polymer, the organic solvent is methyl ethyl ketone.

5. The polymer according to claim 1, characterized in that, It satisfies one or more of the following conditions; (1) In the preparation method of the polymer, the temperature of the polymerization reaction is 60-100 °C; (2) In the preparation method of the polymer, the time of the polymerization reaction is 10-24 hours; (3) In the preparation method of the polymer, the raw materials of the polymerization reaction are the monomer shown in formula A, the monomer shown in formula B, the initiator and the organic solvent; (4) In the preparation method of the polymer, the post-treatment steps after the polymerization reaction are cooling, precipitation and drying; (5) In the preparation method of the polymer, the polymerization reaction is carried out under an inert gas.

6. The polymer according to claim 5, characterized in that, It satisfies one or more of the following conditions; (1) In the preparation method of the polymer, the temperature of the polymerization reaction is 70 °C; (2) In the preparation method of the polymer, the time of the polymerization reaction is 12 hours; (3) In the method for preparing the polymer, the solvent used for precipitation in the post-treatment step after the polymerization reaction is an alkane solvent, such as n-hexane; preferably, the weight ratio of the n-hexane to the organic solvent is (3 - 4):1, preferably 3.3:1; more preferably, the drying is vacuum drying, such as vacuum drying at 50°C for 24 hours; (4) In the method for preparing the polymer, the polymerization reaction is carried out under nitrogen.

7. The polymer according to claim 1, wherein The polymer is any one of the following polymers; Polymer P1: By weight, the weight of the monomer represented by formula A is 2 parts, the weight of the monomer represented by formula B is 1 part, the weight of methyl ethyl ketone is 15 parts, and the weight of azobisisobutyronitrile is 0.1 part; the weight average molecular weight is 5784; Polymer P2: By weight, the weight of the monomer represented by formula A is 4 parts, the weight of the monomer represented by formula B is 1.5 parts, the weight of methyl ethyl ketone is 15 parts, and the weight of azobisisobutyronitrile is 0.1 part; the weight average molecular weight is 7851; Polymer P3: By weight, the weight of the monomer represented by formula A is 5 parts, the weight of the monomer represented by formula B is 2 parts, the weight of methyl ethyl ketone is 15 parts, and the weight of azobisisobutyronitrile is 0.1 part; the weight average molecular weight is 8938; Polymer P4: By weight, the weight of the monomer represented by formula A is 8 parts, the weight of the monomer represented by formula B is 3.5 parts, the weight of methyl ethyl ketone is 15 parts, and the weight of azobisisobutyronitrile is 0.1 part; the weight average molecular weight is 10089; Polymer P5: By weight, the weight of the monomer represented by formula A is 10 parts, the weight of the monomer represented by formula B is 6 parts, the weight of methyl ethyl ketone is 15 parts, and the weight of azobisisobutyronitrile is 0.1 part; the weight average molecular weight is 12157; Among polymers P1 to P5, monomer B is 8. A method for preparing the polymer according to any one of claims 1-7, characterized in that, It includes the following steps: In the presence of an initiator, the monomer represented by formula A and the monomer represented by formula B are polymerized in an organic solvent to obtain the polymer; By weight, the weight of monomer A is 1 - 15 parts; the weight of monomer B is 1 - 10 parts; n is an integer from 1 to 10.

9. The polymer preparation method according to claim 8, wherein, The operation and conditions of the polymerization reaction are the same as those described in any one of claims 2 - 6.

10. Use of a polymer as described in any one of claims 1 - 7 in ArF immersion lithography.

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