Photoresist composition modification method

Abstract

The invention relates to the technical field of photoresist, in particular to a modification method suitable for photoresist. The photoresist is a positive photoresist and comprises phenolic polymer resin, a diazo naphthoquinone type photoinitiator, a solvent and an additive. According to the invention, a multi-carbon-based enol compound is used as a precursor to prepare a diazo naphthoquinone sulfonate type photosensitive compound, an aldehyde group carried in the diazo naphthoquinone sulfonate type photosensitive compound and an amine additive are used for grafting a photoinitiator-phenolic resin coupling product through a Schiff base reaction, and the dissolution inhibition effect of the photoinitiator-phenolic resin coupling product is adjusted; therefore, key characteristics such as resolution, etching resistance, edge roughness after exposure and development and the like of the photoresist are enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of photoresists, and in particular to a modification method suitable for diazonaphthoquinone-phenolic type photoresists. Background Art

[0002] Positive photoresist composed of naphthoquinone diazo type photoinitiator (DNQ) and phenolic resin is the most typical type of photoresist used in G / I line lithography process. DNQ molecules and phenolic hydroxyl groups on phenolic resin form intermolecular hydrogen bonds. DNQ type photoinitiator will couple to the molecular chain of phenolic polymer, reducing its solubility in specific solvents. When DNQ is irradiated with ultraviolet light, its structure changes, the intermolecular hydrogen bonds are destroyed, and the dissociation of DNQ type photoinitiator leads to increased solubility of polymer molecules. Therefore, the exposed part of the photoresist can be dissolved and removed, thereby completing the transfer of the photolithographic pattern.

[0003] The difference in solubility of photoresist before and after exposure is a key factor in achieving accurate pattern transfer resolution. In the design of photoresist, by enhancing the dissolution inhibition of diazonaphthoquinone photoinitiators, the corrosion resistance of unexposed areas can be further improved, thereby reducing unnecessary dissolution during the development process and improving the sharpness and overall fidelity of pattern edges. Currently, there are several main methods to increase the dissolution inhibition of diazonaphthoquinone photoinitiators: 1. Introduce enhanced hydrogen bond donors or acceptors to form strong hydrogen bonds with diazonaphthoquinone molecules, increase the interaction between molecules, thereby enhancing the molecular structure stability of the unexposed area and inhibiting its solubility.

[0004] 2. Optimizing the polarity of the photoresist raw polymer resin. By selecting or synthesizing a more polar polymer matrix material, the hydrogen bonding or other polar interactions of the diazonaphthoquinone molecules in the photoresist can be enhanced, thereby improving the dissolution inhibition effect of the unexposed area.

[0005] 3. Introduce anti-solubility additives and add anti-solubility compounds such as high molecular weight polysaccharides or polymer segments with hydrophobic groups to the photoresist. These additives can increase the overall hydrophobicity and molecular weight of the photoresist by forming complexes with diazonaphthoquinone photoinitiators, thereby significantly reducing the solubility of the unexposed areas.

[0006] Through the above method, the dissolution inhibition effect of the photoresist can be effectively enhanced in the photolithography process, and the resolution and fidelity of the pattern can be improved. In addition, by selecting appropriate additives through the above method, the etching resistance of the photoresist can also be increased to meet the strict requirements of high-density integrated circuit manufacturing. Summary of the invention

[0007] In view of the above reasons, the present invention provides a modification method suitable for photoresist. A diazo naphthoquinone sulfonate type photosensitive compound is prepared by using a multi-carbon enol compound as a precursor, and the aldehyde group carried by the diazo naphthoquinone sulfonate type photosensitive compound is used to graft the photoinitiator-phenolic resin coupling product through a Schiff base reaction with an amine additive, and its dissolution inhibition effect is adjusted, thereby enhancing the key characteristics of the photoresist such as resolution, etching resistance, and edge roughness after exposure and development. .

[0008] To achieve the above-mentioned purpose, according to the first part of the present invention, a photoresist modification method is provided, characterized in that an appropriate amount of amino compound is added to the photoresist composition, and the amino compound structure is grafted onto the coupling product of diazonaphthoquinone photoinitiator and phenolic resin through Schiff base reaction, and its dissolution inhibition effect is adjusted, thereby enhancing the key properties of the photoresist such as resolution, etching resistance and edge roughness after exposure and development.

[0009] Furthermore, the photoresist comprises a phenolic polymer resin, a diazonaphthoquinone type photoinitiator, a solvent and an additive.

[0010] Furthermore, the naphthoquinone diazine photoinitiator in the photoresist has a structure shown in Formula I:

[0011] Formula I Wherein X each independently represents N, C, Si, benzene ring and aromatic heterocycle, R each independently represents hydrogen, halogen, C1-C18 alkyl branched or straight chain, aromatic hydrocarbon, C2-C10 unsaturated hydrocarbon group, C3-C12 cycloalkyl group, wherein k represents any integer between 1 and 4, n represents an integer between 0 and 2, and m represents an integer between 2 and 4.

[0012] Furthermore, the naphthoquinone diazide type photoinitiator is selected from at least one of the following structural compounds:

[0013] Further, the Schiff base reaction process is as follows:

[0014] Furthermore, the naphthoquinone diazide type photoinitiator is prepared by the following method: Step A1, mixing a polycarbonyl enol compound and diazonaphthoquinone sulfonyl chloride in an organic solvent, and reacting by adding an alkaline activator to obtain the diazonaphthoquinone type photoinitiator product system; Step A2, adding hydrochloric acid to the diazonaphthoquinone type photoinitiator system obtained in A1, filtering to remove inorganic salt by-products, and then adding a large amount of water to the organic phase to precipitate the diazonaphthoquinone type photoinitiator.

[0015] Furthermore, the carbonyl enol compound has a structure shown in Formula II:

[0016] Formula II wherein X independently represents N, C, Si, a benzene ring, or an aromatic heterocyclic ring; R independently represents hydrogen, a halogen, a C1-C18 alkyl branched or straight chain, an aromatic hydrocarbon, a C2-C10 unsaturated hydrocarbon group, or a C3-C12 cycloalkyl group; n represents an integer between 0 and 2; and m represents an integer between 2 and 4; Furthermore, the polycarbonyl enol compound is selected from at least one of the following structural compounds: .

[0017] Furthermore, the polycarbonyl enol compound is prepared by the following method: Step A1, synthesizing an acetyl compound by an acylation reaction of a raw aromatic compound; Step A2, synthesizing a carboxylic acid compound by Willgerodt-Kindler reaction; Step A3, preparing a Vilsmeier-Haack-Arnold reagent, adding a carboxylic acid compound to the Vilsmeier-Haack-Arnold reagent to synthesize an onium salt compound; Step A4, hydrolyzing the onium salt compound to obtain a polycarbonyl enol compound; X, R, m, n and the polycarbonyl enol compound have the same meanings as in any one of the above claim 1.

[0018] Furthermore, the molecular weight of the phenolic polymer resin is distributed in the range of 2000-10000.

[0019] Furthermore, according to the weight percentage, it includes 20-30 parts of phenolic polymer resin, 5-8 parts of diazonaphthoquinone type photoinitiator, 60-70 parts of solvent, and 2-6 parts of additives.

[0020] Furthermore, the amino compound is one or more of ethylamine, propylamine, tris(2-aminoethyl)amine, n-butylamine, aniline, benzyl diamine, meta-phenylene triamine, p-methylaniline, and melamine.

[0021] The present invention provides a scheme for preparing a high-performance naphthoquinone sulfonate-type photosensitive compound using the multi-carbon enol compound as a precursor. The photosensitive compound is applied to a photoresist composition, and its dissolution inhibition effect can be adjusted by combining it with an amine additive. The obtained photoresist has high resolution, good sensitivity, excellent thermal stability and anti-etching performance. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further explained below in conjunction with specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The protection scope of the present invention shall be subject to the contents recorded in the claims. Any modification or replacement made by a person skilled in the art to the technical solution of the present invention without creative work shall fall within the protection scope of the present invention.

[0023] In the first typical embodiment of the present application, the present invention provides a photoresist modification method, characterized in that an appropriate amount of amino compound is added to the photoresist composition, and the amino compound structure is grafted onto the coupling product of diazonaphthoquinone photoinitiator and phenolic resin through Schiff base reaction, and its dissolution inhibition effect is adjusted, thereby enhancing the key properties of the photoresist such as resolution, etching resistance, and edge roughness after exposure and development.

[0024] The photoresist comprises phenolic polymer resin, naphthoquinone diazide photoinitiator, solvent and additives.

[0025] Wherein, the naphthoquinone diazine photoinitiator in the photoresist has a structure shown in Formula I:

[0026] Formula I Wherein X each independently represents N, C, Si, benzene ring and aromatic heterocycle, R each independently represents hydrogen, halogen, C1-C18 alkyl branched or straight chain, aromatic hydrocarbon, C2-C10 unsaturated hydrocarbon group, C3-C12 cycloalkyl group, wherein k represents any integer between 1 and 4, n represents an integer between 0 and 2, and m represents an integer between 2 and 4.

[0027] Wherein, the naphthoquinone diazine type photoinitiator is selected from at least one of the following structural compounds:

[0028] Wherein, the naphthoquinone diazide type photoinitiator is prepared by the following method: Step A1, mixing a polycarbonyl enol compound and diazonaphthoquinone sulfonyl chloride in an organic solvent, and reacting by adding an alkaline activator to obtain the diazonaphthoquinone type photoinitiator product system; Step A2, adding hydrochloric acid to the diazonaphthoquinone type photoinitiator system obtained in A1, filtering to remove inorganic salt by-products, and then adding a large amount of water to the organic phase to precipitate the diazonaphthoquinone type photoinitiator.

[0029] Wherein, the carbonyl enol compound has a structure shown in Formula II:

[0030] Formula II wherein X independently represents N, C, Si, a benzene ring, or an aromatic heterocyclic ring; R independently represents hydrogen, a halogen, a C1-C18 alkyl branched or straight chain, an aromatic hydrocarbon, a C2-C10 unsaturated hydrocarbon group, or a C3-C12 cycloalkyl group; n represents an integer between 0 and 2; and m represents an integer between 2 and 4; Wherein, the polycarbonyl enol compound is selected from at least one of the following structural compounds:

[0031] Wherein, the polycarbonyl enol compound is prepared by the following method: Step A1, synthesizing an acetyl compound by an acylation reaction of a raw aromatic compound; Step A2, synthesizing a carboxylic acid compound by Willgerodt-Kindler reaction; Step A3, preparing a Vilsmeier-Haack-Arnold reagent, adding a carboxylic acid compound to the Vilsmeier-Haack-Arnold reagent to synthesize an onium salt compound; Step A4, hydrolyzing the onium salt compound to obtain a polycarbonyl enol compound; X, R, m, n and the polycarbonyl enol compound have the same meanings as in any one of the above claim 1.

[0032] Wherein, the molecular weight of the phenolic polymer resin is distributed in the range of 2000-10000.

[0033] The photoresist configuration is calculated by weight and includes 20-30 parts of phenolic polymer resin, 5-8 parts of diazonaphthoquinone type photoinitiator, 60-70 parts of solvent, and 2-6 parts of additives.

[0034] The amino compound is one or more of ethylamine, propylamine, tri(2-aminoethyl)amine, n-butylamine, aniline, benzyldiamine, meta-phenylenetriamine, p-methylaniline and melamine.

[0035] The beneficial effects of the present application will be further described below with reference to embodiments.

[0036] Example 1 50 g of phenolic polymer resin (a mixture of 2000 molecular weight and 10000 molecular weight resins in a ratio of 1:4) and 10 g of diazonaphthoquinone type photoinitiator S1 were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 10 g of PGMEA to form solution 2. Solutions 1 and 2 were stirred and mixed at room temperature to form a clear solution, and then slowly heated to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 1.

[0037] Example 2 The difference from Example 1 is that p-methylaniline modifier is added 50 g of phenolic polymer resin (a mixture of 2000 molecular weight and 10000 molecular weight resins in a ratio of 1:4) and 10 g of diazonaphthoquinone type photoinitiator S1 were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2, and 2 g of p-methylaniline was dissolved in 5 g of PGMEA to form solution 3. Solutions 1, 2, and 3 were stirred and mixed at room temperature to form a clear solution, and then the temperature was slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 2.

[0038] Example 3 The difference from Example 1 is that an ethylenediamine modifier is added.

[0039] 50 g of phenolic polymer resin (a mixture of 2000 molecular weight and 10000 molecular weight resins in a ratio of 1:4) and 10 g of diazonaphthoquinone type photoinitiator S1 were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2, and 1 g of ethylenediamine was dissolved in 5 g of PGMEA to form solution 3. Solutions 1, 2, and 3 were stirred and mixed at room temperature to form a clear solution, and then the temperature was slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 3.

[0040] Example 4 The difference from Example 2 is that the naphthoquinone diazide type photoinitiator is replaced by S2 from S1.

[0041] 50 g of phenolic polymer resin (a mixture of 2000 molecular weight and 10000 molecular weight resins in a ratio of 1:4) and 10 g of diazonaphthoquinone type photoinitiator S2 were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2, and 2 g of p-methylaniline was dissolved in 5 g of PGMEA to form solution 3. Solutions 1, 2, and 3 were stirred and mixed at room temperature to form a clear solution, and then the temperature was slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 4.

[0042] Example 5 The difference from Example 3 is that the diazonaphthoquinone type photoinitiator is replaced by S2 50 g of phenolic polymer resin (a mixture of resins with a molecular weight of 2000 and 10000 at a ratio of 1:4) and 10 g of diazonaphthoquinone type photoinitiator S2 were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2, and 1 g of ethylenediamine was dissolved in 5 g of PGMEA to form solution 3. Solutions 1, 2, and 3 were stirred and mixed at room temperature to form a clear solution, and then the temperature was slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 5.

[0043] Example 6 The difference from Example 1 is that the photoinitiator is replaced by commercially available 2,3,4,4'-tetrahydroxybenzophenone-2,1,5-diazonaphthoquinone sulfonate instead of S1.

[0044] 50 g of phenolic polymer resin (a mixture of resins with a molecular weight of 2000 and a molecular weight of 10000 at a ratio of 1:4) and 10 g of 2,3,4,4'-tetrahydroxybenzophenone-2,1,5-diazonaphthoquinone sulfonate were dissolved in 135 g of PGMEA solvent to form solution 1. Subsequently, 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2. Solutions 1 and 2 were stirred and mixed at room temperature to form a clear solution. The temperature was then slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 6.

[0045] Example 7 The difference from Example 6 is that p-methylaniline modifier is added.

[0046] 50 g of phenolic polymer resin (a mixture of a molecular weight of 2000 and a molecular weight of 10000 at a ratio of 1:4) and 10 g of 2,3,4,4'-tetrahydroxybenzophenone-2,1,5-diazonaphthoquinone sulfonate were dissolved in 135 g of PGMEA solvent to form solution 1, and then 2 g of surfactant S-381 was dissolved in 5 g of PGMEA to form solution 2, and 2 g of p-methylaniline was dissolved in 5 g of PGMEA to form solution 3. Solutions 1, 2, and 3 were stirred and mixed at room temperature to form a clear solution, and then the temperature was slowly raised to 50 degrees Celsius and stirred for reaction for 16 hours to obtain a photoresist composition 7.

[0047] Test Example 8 The above-mentioned photoresists 1-7 were respectively coated on the silicon wafer by spin coating, and after vacuum drying, they were baked on a hot plate at a temperature of 110°C for 90 seconds to form a photoresist coating with a coating thickness of about 1.5 μm. Then, a mercury lamp was used as a light source to expose the photoresist coating with a total exposure energy of 200 to 400 mJ / cm 2 . After exposure, it is developed with a tetramethylammonium hydroxide aqueous solution with a mass concentration of 2.38wt%, and the development time is 20s. After washing with water for 30s, it is dried to remove the exposed part to form a photoresist pattern. The photoresist pattern is inspected using a scanning electron microscope to compare the resolution of the photoresist. The resolution is based on the minimum line width that can be achieved. The resolution test results of different photoresist patterns are shown in Table 1: Table 1

[0048] The resolution results show that the minimum resolution of composition 2 tested is 1.3 μm, which is the lowest compared to the other six compositions and has the best performance.

[0049] Test Example 2 The above-mentioned photoresists 1-7 are respectively coated on a silicon wafer by spin coating, and after vacuum drying, they are baked on a hot plate at a temperature of 110°C for 90 seconds to form a photoresist coating with a coating thickness of about 1.5μm. Then, a mercury lamp is used as a light source to expose the photoresist coating, and the total exposure energy is 200-400mJ / cm2. After exposure, it is developed with a tetramethylammonium hydroxide aqueous solution with a mass concentration of 2.38wt%, and the development time is 20s. After washing with water for 30s, it is dried to remove the exposed part to form a photoresist pattern.

[0050] After the exposure and development, the silicon wafer was measured for the thickness of the photoresist film, and then immersed in the etching solution (HF type) for 10 minutes, the etching solution on the surface was rinsed off, the residual photoresist film thickness was measured, and the difference in film thickness before and after etching was calculated. The results are shown in Table 2: Table 2

[0051] The difference in film thickness before and after etching shows that the difference in the test of composition 2 is 0.2 μm, which is the lowest compared with the other six compositions, and its performance is the best.

Claims

1. A photoresist modification method, characterized in that: An appropriate amount of amino compound is added to the photoresist composition, and the amino compound structure is grafted onto the coupling product of diazonaphthoquinone photoinitiator and phenolic resin through Schiff base reaction, so as to adjust its dissolution inhibition effect, thereby enhancing the key properties of the photoresist such as resolution, etching resistance and edge roughness after exposure and development.

2. The photoresist modification method according to claim 1, characterized in that: The photoresist comprises a phenolic polymer resin, a diazonaphthoquinone type photoinitiator, a solvent and an additive.

3. The photoresist modification method according to claim 1, characterized in that: The naphthoquinone diazine photoinitiator in the photoresist has a structure shown in Formula I: Formula I Wherein X each independently represents N, C, Si, benzene ring and aromatic heterocycle, R each independently represents hydrogen, halogen, C1-C18 alkyl branched or straight chain, aromatic hydrocarbon, C2-C10 unsaturated hydrocarbon group, C3-C12 cycloalkyl group, wherein k represents any integer between 1 and 4, n represents an integer between 0 and 2, and m represents an integer between 2 and 4.

4. The naphthoquinone diazide photoinitiator according to claim 3, characterized in that: The naphthoquinone diazide photoinitiator is selected from at least one of the following structural compounds (Figure 1): 。 5. The photoresist modification method according to claim 1, characterized in that: The Schiff base reaction process is as follows: 。 6. The naphthoquinone diazide photoinitiator according to claim 3, characterized in that: The naphthoquinone diazide type photoinitiator is prepared by the following method: Step A1, mixing a polycarbonyl enol compound and diazonaphthoquinone sulfonyl chloride in an organic solvent, and reacting by adding an alkaline activator to obtain the diazonaphthoquinone type photoinitiator product system; Step A2, adding hydrochloric acid to the diazonaphthoquinone type photoinitiator system obtained in A1, filtering to remove inorganic salt by-products, and then adding a large amount of water to the organic phase to precipitate the diazonaphthoquinone type photoinitiator.

7. The method for preparing a naphthoquinone diazide photoinitiator according to claim 6, characterized in that: The carbonyl enol compound has a structure shown in Formula II: Formula II Wherein X each independently represents N, C, Si, benzene ring and aromatic heterocycle, R each independently represents hydrogen, halogen, C1-C18 alkyl branched or straight chain, aromatic hydrocarbon, C2-C10 unsaturated hydrocarbon group, C3-C12 cycloalkyl group, n represents an integer between 0 and 2, and m represents an integer between 2 and 4.

8. The polycarbonyl enol compound according to claim 7, characterized in that The polycarbonyl enol compound is selected from at least one of the following structural compounds: 。 9. The polycarbonyl enol compound according to claim 7, characterized in that The polycarbonyl enol compound is prepared by the following method: Step A1, synthesizing an acetyl compound by an acylation reaction of a raw aromatic compound; Step A2, synthesizing a carboxylic acid compound by Willgerodt-Kindler reaction; Step A3, preparing a Vilsmeier-Haack-Arnold reagent, adding a carboxylic acid compound to the Vilsmeier-Haack-Arnold reagent to synthesize an onium salt compound; Step A4, hydrolyzing the onium salt compound to obtain a polycarbonyl enol compound; X, R, m, n and the polycarbonyl enol compound have the same meanings as in any one of the above claim 1.

10. The photoresist according to claim 2, characterized in that: The molecular weight of the phenolic polymer resin is distributed in the range of 2000-10000.

11. The photoresist according to claim 1, characterized in that: According to the weight percentage, the composition comprises 20-30 parts of phenolic polymer resin, 5-8 parts of diazonaphthoquinone type photoinitiator, 60-70 parts of solvent and 2-6 parts of additive.

12. The photoresist modification method according to claim 1, characterized in that: The amino compound is one or more of ethylamine, propylamine, tri(2-aminoethyl)amine, n-butylamine, aniline, benzyldiamine, meta-phenylenetriamine, p-methylaniline and melamine.

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