A photoresist composition and preparation method thereof

Abstract

An embodiment of the present invention provides a photoresist composition and a preparation method thereof, the photoresist composition comprising the following raw materials: 0.1-10 weight components of a photoacid generator, 10-30 weight components of a film-forming resin, 0.1-5 weight components of an acid diffusion inhibitor, and 55-89.8 weight components of an organic solvent A; wherein the photoacid generator is a photoacid generator containing a diester structure, and the acid diffusion inhibitor is an acid diffusion inhibitor containing a hydroxyl functional unit and a basic functional unit. The photoresist composition provided by the embodiment of the present invention, under the condition of using a photoacid generator containing a diester structure, further improves the line width roughness of the photoresist, improves the resolution of the photoresist, and enhances the film-forming ability of the photoresist by adding the acid diffusion inhibitor containing a hydroxyl functional unit and a basic functional unit.

Description

Technical Field

[0001] The present invention relates to the technical field of photoresists, and in particular to a photoresist composition and a preparation method thereof. Background Art

[0002] Photoresist (also known as photoresist) is an etch-resistant thin film material whose solubility changes when exposed to light sources such as ultraviolet light, excimer lasers, electron beams, ion beams, and X-rays. It is primarily used in the microfabrication of integrated circuits and discrete semiconductor devices, but is also widely used in the manufacturing of flat-panel displays, LEDs, flip-chip packages, magnetic heads, and precision sensors. Due to its photochemical sensitivity, photoresist can be used to undergo photochemical reactions. The remaining portion of the photoresist after exposure and development protects the underlying substrate. Etching with an etchant then transfers the desired fine pattern from the mask to the substrate being processed. In addition to the main resin and photoacid generator, photoresists often also include an acid diffusion inhibitor. Its main function is to prevent the dissolution of the film-forming resin before exposure, acting as a dissolution inhibitor. After exposure, the acid generated by the photoacid generator in the photoresist catalyzes the removal of acid-sensitive groups, turning the acid diffusion inhibitor into a polar compound, thereby promoting the dissolution of the resin, thereby increasing the dissolution contrast between the non-exposed and exposed areas and improving the resolution of the resist. Currently, the acid diffusion inhibitors available for photoresists on the market simply add a certain number of hydroxyl groups to the structure to enhance its compatibility with the resin, but do not provide a technical solution for further improving the resolution of the photoresist. Therefore, the prior art still needs to be improved. Summary of the Invention

[0003] An embodiment of the present invention provides a photoresist composition and a preparation method thereof. The photoresist composition improves the line width and roughness of a circuit fabricated using the photoresist by using a photoacid generator containing a diester structure that helps generate an effective, controllable, large-volume acid. Furthermore, an acid diffusion inhibitor containing a hydroxyl functional unit and a basic functional unit is used in the photoresist to further improve the resolution of the photoresist.

[0004] The embodiment of the present invention provides a photoresist composition, comprising the following raw materials: 0.1-10 weight components of a photoacid generator, 10-30 weight components of a film-forming resin, 0.1-5 weight components of an acid diffusion inhibitor, and 55-89.8 weight components of an organic solvent A;

[0005] The photoacid generator is a photoacid generator containing a diester structure, and its specific structural formula is as follows:

[0006]

[0007] wherein R1 and R2 are one or more of an alkyl group having 1 to 40 hydrogen atoms and 1 to 20 carbon atoms, an aryl group, or a substituent containing a sulfur / oxygen heteroatom, and Q+ is a sulfonium salt cation or an iodonium salt cation;

[0008] The specific structural formula of the acid diffusion inhibitor is:

[0009]

[0010] Wherein, in the general formula (2), R1 and R2 are H or methyl, R3 and R4 are one or more of an alkyl group having 1 to 40 hydrogen atoms and 1 to 20 carbon atoms, an aryl group, or a substituent containing sulfur / oxygen / nitrogen heteroatoms, n is 5-200, n a is one or more of an alkyl group, an aryl group, or a functional structure containing sulfur / oxygen / nitrogen heteroatoms, n b It is a carbon chain containing one or more ether bonds, one or more ester bonds and having 1 to 20 carbon atoms, including n a The part with hydroxyl structure is hydroxyl functional unit, including R3, R4 and n b The part is the basic functional unit.

[0011] Preferably, in the photoresist composition, the preparation method of the photoacid generator containing a diester structure is:

[0012] S1, dissolving maleic anhydride in organic solvent B, adding an alcohol organic compound and a catalyst, stirring evenly and then heating to carry out esterification reaction to obtain a succinate compound;

[0013] S2, mixing the succinate compound and sulfite in an aqueous solution and then heating them to react to obtain a diester sulfonate;

[0014] S3, mixing the diester sulfonate with an aqueous solution containing a sulfonium salt cation or an iodonium salt cation to generate the diester structure-containing photoacid generator.

[0015] More preferably, in the photoresist composition, the organic solvent B is one or more of toluene, dichloroethane or 4-dimethylaminopyridine; and the catalyst is one or more of concentrated sulfuric acid and p-toluenesulfonic acid.

[0016] More preferably, in the photoresist composition, the alcohol organic compound is a saturated alcohol organic compound; and the sulfite is sodium sulfite or potassium sulfite.

[0017] More preferably, in the photoresist composition, the temperature of the esterification reaction in S1 is 50-110°C, and the temperature of the reaction in S2 is 50-110°C.

[0018] Preferably, in the photoresist composition, the film-forming resin is prepared by at least one acid-reactive monomer, and the specific structural formula of the acid-reactive monomer is:

[0019]

[0020] Among them, R a is H or a carbon chain with 1 to 20 carbon atoms; R b is an acid-sensitive quaternary carbon, R c is H or a carbon chain with 1 to 20 carbon atoms; R d It is a (meth)acrylate containing a polar group.

[0021] More preferably, in the photoresist composition, the R b It is a quaternary ester with a carbon number of 6 to 30, in which the hydrogen atoms of the carbon atoms connected to the hydroxyl oxygen atom are all replaced by other groups, and its structure is one or more of tert-butyl ester, substituted tert-butyl ester, alkyl-substituted adamantane ester, alkyl-substituted adamantane derivative ester, alkyl-substituted norbornane ester, alkyl-substituted norbornane derivative ester, alkyl-substituted cyclic alkyl ester, and alkyl-substituted cyclic alkyl derivative ester.

[0022] More preferably, in the photoresist composition, the film-forming resin is added with an initiator, an organic solvent C and a precipitant during the preparation process, wherein the initiator is an azo initiator or a peroxide free radical initiator, the amount of the initiator is 0.3% to 15% of the total mass of the comonomer, the organic solvent C is 50% to 80% of the total mass of the comonomer, and the precipitant is 4 to 6 times the total mass of the comonomer.

[0023] More preferably, in the photoresist composition, the azo initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile; the peroxide free radical initiator is one or more of tert-butyl peroxypivalate, tert-butyloxy hydroperoxide, benzoic acid hydroperoxide or benzoyl peroxide; the organic solvent C is one or more of methanol, ethanol, dioxane, acetone, methyl ethyl ketone, tetrahydrofuran, methyltetrahydrofuran, benzene, toluene, xylene, chloroform, dichloroethane, trichloroethane, and ethyl acetate; and the precipitant is one or more of pure water, methanol, methanol / water mixture, ethanol, ethanol / water mixture, isopropanol, isopropanol / water mixture, n-heptane, n-hexane, cyclohexane, n-pentane, petroleum ether, ethyl ether, and methyl tert-butyl ether.

[0024] Preferably, in the photoresist composition, the organic solvent A is one or more of methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol monoacetate, propylene glycol monoethyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, butyl acetate, neopentyl acetate, ethyl lactate, methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone.

[0025] The present invention also provides a method for preparing a photoresist composition. The preparation method comprises the following steps: mixing and dissolving the above components and then shaking the mixture in the dark; after shaking, filtering the mixture and collecting the filtrate, which is the photoresist composition.

[0026] The photoresist composition described in the embodiment of the present invention improves the line width and roughness of the circuit manufactured using the photoresist by using a photoacid generator containing a diester structure that helps generate effective controllable large-volume acid in the photoresist. At the same time, the use of an acid diffusion inhibitor with an ester bond in the photoresist can more effectively improve the distribution of the acid diffusion inhibitor itself within the photoresist, further improving the resolution and line width roughness of the photoresist and improving the film-forming ability of the photoresist. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photoresist pattern obtained by photolithography of the photoresist composition prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] During the preparation process of the photoresist composition described in the embodiments of the present invention, a photoacid generator containing a diester structure is employed. As a result, after exposure, the diester-containing photoacid generator in the photoresist generates an effective and controllable large-volume acid. Together with the acid inhibitor, this exhibits excellent acid diffusion properties, allowing for smooth chemical amplification reactions in the exposed areas and effectively inhibiting acid diffusion at the interface between the exposed and non-exposed areas, significantly improving line roughness. Furthermore, by adding an acid diffusion inhibitor containing both hydroxyl and alkaline functional units to the diester-containing photoacid generator, the distribution of the acid diffusion inhibitor within the photoresist is more effectively improved, further enhancing the resolution and line width roughness of the photoresist and improving the film-forming ability of the photoresist.

[0030] Example 1

[0031] A method for preparing a photoresist composition, comprising:

[0032] Take 0.25g of a photoacid generator containing a diester structure, 8.5g of a film-forming resin, 0.06g of an acid diffusion inhibitor, and 80g of an organic solvent A, mix them evenly in a 100mL glass bottle, and shake them in the dark for 24 hours. After the shaking is completed, the mixture is first filtered through a 0.22-micron filter and then filtered through a 0.02-micron filter. The collected filtrate is the photoresist composition.

[0033] Specifically, the preparation method of the photoacid generator containing a diester structure is as follows:

[0034] S1. Under nitrogen protection, 98 g of maleic anhydride was dissolved in 100 g of toluene, and 220 g of cyclohexanol and 50 g of p-toluenesulfonic acid were added. After stirring evenly, the temperature was raised to 90 ° C. and the esterification reaction was carried out for 12 h. 100 g of ethyl acetate was added and washed twice with 50 mL of deionized water. The organic layer was then dried and desolventized to obtain 162 g of succinate compound. The conversion rate was measured to be 58%. The reaction equation is:

[0035]

[0036] S2. 56 g of the succinate compound was dissolved in 200 g of deionized water, 25 g of sodium sulfite was added, the mixture was mixed evenly, and the mixture was reacted at 100 ° C for 24 h. After the reaction was completed, 500 g of ethyl acetate was used for extraction, and then desolventization was performed to obtain 47 g of a sodium diester sulfonate compound. The conversion rate was measured to be 61%, and the reaction equation was:

[0037]

[0038] S3. 38 g of the sodium diester sulfonate compound was dissolved in 100 g of deionized water, and 150 g of a triphenylsulfonium chloride aqueous solution (mass fraction 20%) was added dropwise. After stirring for 12 h, the mixture was extracted with 500 g of dichloromethane, and then washed twice with 50 g of deionized water. After washing, the mixture was dried over anhydrous magnesium sulfate and desolventized to obtain 38 g of a photoacid generator containing a diester structure. The conversion rate was measured to be 62%, and the reaction equation was:

[0039]

[0040] Wherein, the structural formula of the acid diffusion inhibitor is:

[0041]

[0042] The film-forming resin is prepared by adding 45g of monomer 1, 50g of monomer 2, and 20g of monomer 3 into a reactor filled with nitrogen, adding 60g of ethyl acetate into the reactor, stirring evenly to obtain a monomer mixture, then heating the reactor to 77°C, mixing 10g of ethyl acetate and 12g of benzoyl peroxide to obtain an initiator mixture, adding the initiator mixture dropwise to the reactor containing the monomer mixture, reacting at 77°C for 7 hours, stopping the reaction, cooling the reactor to room temperature, then adding 600g of methanol into the reactor cooled to room temperature, generating a first precipitate after 1 hour, draining the liquid in the reactor, and then adding 70g of ethyl acetate into the reactor until the first precipitate dissolves. Adding 600g of methanol into the reactor to generate a second precipitate, draining the liquid in the reactor to obtain a second precipitate, and drying the second precipitate in a vacuum to obtain 76g of methacrylate resin, with a conversion rate of 66%. The structural formula of the film-forming resin is:

[0043] The molecular weight of the film-forming resin obtained in this example was measured by GPC equipment, and Mw=8655, PDI=1.46,

[0044] In addition, the structural formulas of monomer 1, monomer 2, and monomer 3 are as follows:

[0045] The organic solvent A is a mixture of methyl ether acetate and propylene glycol monoethyl ether, wherein the mass ratio of methyl ether acetate to propylene glycol monoethyl ether is 2:3. The filter is a filter made of nylon or UPE. In this embodiment, a nylon filter is preferred.

[0046] The photoresist composition prepared above was rotated at a speed of 2500 rpm on a No. 12 silicon wafer to form a film, and then baked on a hot plate at 120°C for 90 seconds. After baking, the film was exposed on an exposure machine at an exposure intensity of 45 mJ / cm 2 After exposure, it was baked on a 110℃ hot plate for 90s, and finally developed in 2.38% TMAH developer for 60s, and then dried and examined under an electron microscope. The obtained photolithographic image is as follows Figure 1 As shown, from Figure 1 It can be seen that the photoresist prepared in the embodiment of the present invention reduces the line width and line width roughness of the fabricated circuit. The photoacid generator containing a diester structure can generate effective controllable large-volume acid, which can be used together with an acid diffusion inhibitor to prepare high-resolution photoresist, thereby improving the resolution of the photoresist. The acid inhibitor contains hydroxyl groups, which further increases its polarity and solubility in the resin, and then dissolves evenly with the photoacid generator, thereby improving the adhesion after film formation and improving the overall performance of the photoresist.

[0047] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. A photoresist composition, characterized in that The method comprises the following raw materials: 0.1-10 weight components of a photoacid generator, 10-30 weight components of a film-forming resin, 0.1-5 weight components of an acid diffusion inhibitor, and 55-89.8 weight components of an organic solvent A; The photoacid generator is a photoacid generator containing a diester structure, and its specific structural formula is as follows: Wherein, in the general formula (1), R1 and R2 are alkyl groups having 1 to 40 hydrogen atoms and 1 to 20 carbon atoms, and Q+ is a sulfonium salt cation or an iodonium salt cation; Wherein, the acid diffusion inhibitor is: Wherein, n in the general formula (2) is 5-200; The preparation method of the photoacid generator containing a diester structure is as follows: S1. Dissolving maleic anhydride in an organic solvent B, adding an alcohol organic compound and a catalyst, stirring evenly, and then heating to carry out an esterification reaction to obtain a succinate compound; wherein the alcohol organic compound is a saturated alcohol organic compound, and the catalyst is one or more of concentrated sulfuric acid and p-toluenesulfonic acid; S2, mixing the succinate compound and sulfite in an aqueous solution and then heating them to react to obtain a diester sulfonate; S3, mixing the diester sulfonate with an aqueous solution containing a sulfonium salt cation or an iodonium salt cation to generate the diester structure-containing photoacid generator.

2. The photoresist composition according to claim 1, wherein The organic solvent B is one or more of toluene, dichloroethane or 4-dimethylaminopyridine; and the sulfite is sodium sulfite or potassium sulfite.

3. The photoresist composition according to claim 1, wherein The temperature of the esterification reaction in S1 is 50-110°C, and the temperature of the reaction in S2 is 50-110°C.

4. The photoresist composition according to claim 1, wherein The film-forming resin is prepared by using at least one acid-reactive monomer, and the specific structural formula of the acid-reactive monomer is: Among them, R a is H or a carbon chain with 1 to 20 carbon atoms; R b is an acid-sensitive quaternary carbon, R c is H or a carbon chain with 1 to 20 carbon atoms; R d It is a (meth)acrylate containing a polar group.

5. The photoresist composition according to claim 4, characterized in that The R b It is a quaternary ester with 6 to 30 carbon atoms, in which all the hydrogen atoms of the carbon atoms connected to the hydroxyl oxygen atoms are replaced by other groups. Its structure is one or more of tert-butyl ester, substituted tert-butyl ester, alkyl-substituted adamantane ester, alkyl-substituted norbornyl ester, and alkyl-substituted cyclic alkyl ester.

6. The photoresist composition according to claim 5, characterized in that During the preparation process of the film-forming resin, an initiator, an organic solvent C and a precipitant are added, wherein the initiator is an azo initiator or a peroxide free radical initiator, the amount of the initiator is 0.3% to 15% of the total mass of the comonomer, the amount of the organic solvent C is 50% to 80% of the total mass of the comonomer, and the amount of the precipitant is 4 to 6 times the total mass of the comonomer.

7. The photoresist composition according to claim 6, wherein The azo initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile; the peroxide free radical initiator is one or more of tert-butyl peroxypivalate, tert-butyloxy hydroperoxide, benzoic acid hydroperoxide or benzoyl peroxide; the organic solvent C is one or more of methanol, ethanol, dioxane, acetone, methyl ethyl ketone, tetrahydrofuran, methyltetrahydrofuran, benzene, toluene, xylene, chloroform, dichloroethane, trichloroethane and ethyl acetate; the precipitant is one or more of pure water, methanol, methanol / water mixture, ethanol, ethanol / water mixture, isopropanol, isopropanol / water mixture, n-heptane, n-hexane, cyclohexane, n-pentane, petroleum ether, ethyl ether and methyl tert-butyl ether.

8. The photoresist composition according to claim 1, wherein The organic solvent A is one or more of propylene glycol methyl ether acetate, propylene glycol monoacetate, propylene glycol monoethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, butyl acetate, neopentyl acetate, ethyl lactate, methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone.

9. A method for preparing a photoresist composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: After the components are mixed and dissolved, the mixture is shaken in the dark. After the shaking is completed, the mixed solution is filtered, and the collected filtrate is the photoresist composition.

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