ArF photoresist resin with low edge roughness and preparation method thereof

Abstract

The invention is applicable to the technical field of semiconductor manufacturing materials, and provides ArF photoresist resin with low edge roughness and a preparation method thereof, the ArF photoresist resin is prepared from the monomers in percentage by weight: 40%-60% of lactone monomer, 40%-60% of acid protection monomer and 0.1%-20% of flexible monomer. By introducing the flexible acrylate monomer with lower glass-transition temperature, the flexibility of chain segments of resin molecules can be increased, the glass-transition temperature of the resin can be reduced, chain entanglement among the resin molecules can be reduced, and the photoresist can be dissolved more uniformly in the developing process, so that a photoetching pattern with lower edge roughness can be obtained. The photoresist prepared from the ArF photoresist resin disclosed by the invention has excellent graphic morphology and edge roughness, and the product yield in the manufacturing process of an integrated circuit is improved.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor manufacturing materials, and in particular relates to a photoresist with low edge roughness and a preparation method thereof. Background Art

[0002] The edge roughness (LWR) of ArF (argon fluoride) photoresist usually refers to the flatness and smoothness of the edge area of ​​the photoresist pattern during the photolithography process. The edge roughness will directly affect the quality of the photolithography pattern and the effect of subsequent processing steps. The specific edge roughness can usually be measured by scanning electron microscopy (SEM) or atomic force microscopy (AFM). The edge roughness of photoresist is of great significance, mainly reflected in the following aspects:

[0003] 1. Pattern quality: Edge roughness affects the clarity and accuracy of photolithography patterns. If the photoresist edge is rough, it may cause the pattern to be blurred or distorted, thus affecting subsequent process steps such as etching and deposition.

[0004] 2. Electrical performance: In semiconductor devices, edge roughness may affect the electrical characteristics of the device, such as leakage current, threshold voltage, etc. Rough edges may cause uneven electric field distribution, thus affecting the performance of the device.

[0005] 3. Manufacturing yield: Higher edge roughness may lead to defects such as short circuits, open circuits, etc., which ultimately affect the manufacturing yield. Controlling edge roughness is crucial to improving production efficiency and yield.

[0006] 4. Optical properties: In optical devices, edge roughness affects the propagation and reflection characteristics of signals, which is particularly important for optical systems that require high precision.

[0007] 5. Subsequent processing: Many subsequent processes (such as metal deposition, surface treatment, etc.) are sensitive to the roughness of the photoresist edge. The smoothness of the edge has a direct impact on its adhesion to other materials.

[0008] 6. Equipment and material compatibility: Different photoresists and equipment have different tolerances for edge roughness, so when selecting and optimizing the process, edge roughness management is also an important part of ensuring equipment and material compatibility. Therefore, controlling and optimizing the edge roughness of ArF photoresist is an important factor in improving semiconductor manufacturing quality and efficiency.

[0009] The edge roughness of ArF photoresist is affected by many factors, including the characteristics of the photoresist material itself, the photoresist coating process, the photoresist process, the development process, etc. By precisely controlling these factors, the edge roughness of ArF photoresist can be effectively reduced, thereby improving the accuracy of the photoresist pattern and the manufacturing efficiency of high-quality processes. However, in the advanced semiconductor manufacturing process below 40nm, the requirements for the edge roughness of ArF photoresist have been increasing. Simply adjusting the manufacturing process can no longer meet the current demand for smaller edge roughness. Therefore, it is necessary to improve the characteristics of the photoresist material itself to reduce the edge roughness of ArF photoresist and meet the development needs of today's advanced semiconductor manufacturing technology. Summary of the invention

[0010] In view of the deficiencies of the prior art, the present invention provides an ArF photoresist resin with low edge roughness, aiming to solve the technical problem of high edge roughness of the photoresist in the prior art.

[0011] The embodiment of the present invention is implemented as follows: an ArF photoresist resin with low edge roughness is made of the following monomers, and the proportion of each monomer is as follows by weight percentage:

[0012] 10% to 40% lactone monomer, 20% to 60% acid protection monomer, 0.1% to 20% flexible monomer;

[0013] The flexible monomer has the following structure:

[0014]

[0015] Where: R 13 , R 17 is H or CH3; R 14 , R 15 , R 16 , R 18 , R 20 Same or different, C m H 2m+1 , m is an integer from 0 to 4, R 19 C n H 2n , n is an integer from 0 to 4.

[0016] Furthermore, the R of the flexible monomer 14 , R 15 , R 16 same.

[0017] Furthermore, the R of the flexible monomer 18 , R 20 same.

[0018] Furthermore, the flexible monomer is one type of flexible monomer in the structure.

[0019] Furthermore, the flexible monomer is a mixture of multiple flexible monomers of the structure.

[0020] Preferably, the flexible monomer is butyl acrylate.

[0021] Preferably, the flexible monomer is hydroxyethyl methacrylate.

[0022] Further, the lactone monomer has the following structure:

[0023]

[0024] Wherein: R1, R3, R5, R7 are H or CH3; R2, R4, R6, R8 are C x H 2x , x is an integer from 1 to 4.

[0025] Furthermore, the inner fat monomer is one of the inner fat monomers of the structure.

[0026] Furthermore, the inner fat monomer is a mixture of multiple inner fat monomers of the structure.

[0027] Preferably, the lactone monomer is 2-carboxy-4-norbornyl lactone-5-methylacrylate.

[0028] Furthermore, the acid protection monomer has the following structure:

[0029]

[0030] Among them: R9, R 11 is H or CH3; R 10 , R 12 C y H 2y+1 , y is an integer from 0 to 4.

[0031] Furthermore, the acid-protecting monomer is one of the acid-protecting monomers of the structure.

[0032] Furthermore, the acid-protecting monomer is a mixture of multiple acid-protecting monomers of the structure.

[0033] Preferably, the acid protection monomer is 2-methyl-2-methylacrylate adamantyl ester.

[0034] Furthermore, the ratio of the monomers is: 10% to 40% of lactone monomer, 20% to 60% of acid protection monomer, and 1% to 20% of flexible monomer.

[0035] Furthermore, the ratio of the monomers is: 10% to 40% of lactone monomer, 20% to 60% of acid protection monomer, and 10% to 20% of flexible monomer.

[0036] Preferably, the ratio of the monomers is: 10% to 40% of lactone monomer, 20% to 60% of acid protection monomer, and 15% of flexible monomer.

[0037] More preferably, the ratio of the monomers is: 35% lactone monomer, 50% acid protection monomer, and 15% flexible monomer.

[0038] The present invention also provides a method for preparing an ArF photoresist resin with low edge roughness, comprising the following steps:

[0039] (1) 10% to 40% of lactone monomer, 20% to 60% of acid protection monomer and 0.1% to 20% of flexible monomer are added into a reactor filled with nitrogen, tetrahydrofuran is added into the reactor, and after stirring evenly, the reactor is heated to 65-67° C., then a tetrahydrofuran solution of azobisisobutyronitrile is added dropwise into the reactor, and the reaction is stirred at 65-67° C. for 3 hours, and then the reaction is stopped and the reactor is cooled to room temperature; the flexible monomer has the following structure:

[0040]

[0041] Where: R 13 , R 17 is H or CH3; R 14 , R 15 , R 16 , R 18 , R 20 Same or different, C m H 2m+1 , m is an integer from 0 to 4, R 19 C n H 2n , n is an integer from 0 to 4.

[0042] (2) adding methanol 10 times the mass of the reaction solution into the reaction kettle cooled to room temperature in step (1) and stirring evenly to produce precipitation for 1 hour to obtain a solid precipitate, which is then placed in a vacuum dryer to obtain an ArF photoresist resin.

[0043] The present invention also provides a photoresist prepared from the ArF photoresist resin.

[0044] The ArF photoresist resin of the present invention can be configured into a photoresist according to the following formula:

[0045] The photoresist can be prepared by uniformly mixing ArF photoresist resin, photosensitizer, propylene glycol methyl ether acetate and propylene glycol methyl ether according to a certain proportion.

[0046] The photolithography process conditions of the photoresist are as follows: baking at 110°C for 2 min, exposure energy of 20 mj / cm2, and development time of 60 s to obtain the photolithography pattern.

[0047] The photoresist resin prepared by the present invention is formulated into ArF photoresist, and then a photoresist pattern is obtained through baking, exposure, development and drying processes. The results show that the properties of the ArF photoresist pattern are more uniform and the edge roughness is smaller.

[0048] The beneficial effects achieved by the present invention are as follows: during the preparation process of ArF photoresist resin, flexible monomers are added. Such monomers have low molecular structure rigidity and low molecular interaction, and can reduce the glass transition temperature of the resin, making the resin molecular chain segments more easily move, so they are called flexible monomers. The molecules of general ArF photoresist resins are highly rigid, easily entangled with each other, and the molecular chain segments are difficult to move and form local agglomerations. They are difficult to dissolve during the development process, and are unevenly dispersed in the material, resulting in uneven final graphics and poor edge roughness.

[0049] The photoresist resin with added flexible monomers has low molecular rigidity, and the chain segments are relatively easy to move without chain entanglement. It can be dissolved evenly during the development process, which improves the edge roughness of the ArF photoresist and increases the product yield in the subsequent integrated circuit manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is the photolithography pattern provided in Comparative Example 1.

[0051] Figure 2 It is the photolithography pattern provided in Example 1 of the present invention.

[0052] Figure 3 It is the photolithography pattern provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] Comparative Example 1

[0055] (1) 40 g of 2-carboxy-4-bornyl lactone-5-methylacrylate and 60 g of 2-methyl-2-methylacrylate adamantyl ester were added to a reactor filled with nitrogen, 100 g of tetrahydrofuran was added to the reactor, and the temperature of the reactor was raised to 65-67° C. after stirring evenly, and then a solution of 10 g of azobisisobutyronitrile and 20 g of tetrahydrofuran was added dropwise to the reactor for 3 hours, and the reaction was stirred at 65-67° C. for another 3 hours, and then the reaction was stopped and the reactor was cooled to room temperature. The percentages are weight percentages;

[0056] (2) adding methanol 10 times the mass of the reaction solution to the reaction vessel cooled to room temperature in step (1) and stirring evenly to produce precipitation for 1 hour to obtain a solid precipitate, and placing the solid precipitate in a vacuum dryer to obtain an ArF photoresist resin;

[0057] (3) ArF photoresist resin was prepared into photoresist according to the following formula: 2g ArF photoresist resin, 0.1g photosensitizer P-1, 12g propylene glycol methyl ether acetate and 2g propylene glycol methyl ether; photolithography process conditions: baking at 110°C for 2min, exposure energy: 20mj / cm2, development time 60s, photolithography pattern see Figure 1 shown.

[0058] from Figure 1 It can be seen that the lithography pattern is jagged and has relatively large edge roughness.

[0059] The structural formula of photosensitizer P-1 is as follows:

[0060]

[0061] Example 1

[0062] (1) 35 g of 2-carboxy-4-bornyl lactone-5-methylacrylate, 50 g of 2-methyl-2-methylacrylate adamantyl and 15 g of butyl acrylate were added to a reactor filled with nitrogen, 100 g of tetrahydrofuran was added to the reactor, and the temperature of the reactor was raised to 65-67° C. after stirring evenly, and then a solution of 10 g of azobisisobutyronitrile and 20 g of tetrahydrofuran was added dropwise to the reactor for 3 hours, and the reaction was stirred at 65-67° C. for another 3 hours, and then the reaction was stopped and the reactor was cooled to room temperature. The percentages are weight percentages;

[0063] (2) adding methanol 10 times the mass of the reaction solution to the reaction vessel cooled to room temperature in step (1) and stirring evenly to produce precipitation for 1 hour to obtain a solid precipitate, and placing the solid precipitate in a vacuum dryer to obtain an ArF photoresist resin;

[0064] (3) ArF photoresist resin was prepared into photoresist according to the following formula: 2g ArF photoresist resin, 0.1g photosensitizer P-1, 12g propylene glycol methyl ether acetate and 2g propylene glycol methyl ether; photolithography process conditions: baking at 110°C for 2min, exposure energy: 20mj / cm2, development time 60s, photolithography pattern see Figure 2 shown.

[0065] from Figure 2 It can be seen that the lithography pattern is smooth and uniform, with less edge roughness.

[0066] Example 2

[0067] (1) 35 g of 2-carboxy-4-norbornyl lactone-5-methylacrylate, 50 g of 2-methyl-2-methylacrylate adamantyl and 15 g of hydroxyethyl methacrylate were added to a reactor filled with nitrogen, 100 g of tetrahydrofuran was added to the reactor, and the temperature of the reactor was raised to 65-67° C. after stirring evenly, and then a solution of 10 g of azobisisobutyronitrile and 20 g of tetrahydrofuran was added dropwise to the reactor for 3 hours, and the reaction was stirred at 65-67° C. for another 3 hours, and then the reaction was stopped and the reactor was cooled to room temperature. The percentages are weight percentages;

[0068] (2) adding methanol 10 times the mass of the reaction solution to the reaction vessel cooled to room temperature in step (1) and stirring evenly to produce precipitation for 1 hour to obtain a solid precipitate, and placing the solid precipitate in a vacuum dryer to obtain an ArF photoresist resin;

[0069] (3) ArF photoresist resin was prepared into photoresist according to the following formula: 2g ArF photoresist resin, 0.1g photosensitizer P-1, 12g propylene glycol methyl ether acetate and 2g propylene glycol methyl ether; photolithography process conditions: baking at 110°C for 2min, exposure energy: 20mj / cm2, development time 60s, photolithography pattern see Figure 3 shown.

[0070] from Figure 3 It can be seen that the lithography pattern is smooth and uniform, with less edge roughness.

[0071] The ArF photoresist resin of the present invention adds a flexible monomer during the preparation process, thereby improving the flexibility of the photoresist resin molecules, reducing the entanglement and agglomeration of the resin molecule chains, reducing the edge roughness of the photoresist, improving the photoresist performance, and improving the product yield in the subsequent integrated circuit manufacturing process.

[0072] It is understandable that those skilled in the art can, under the guidance of the above embodiments, combine various implementation methods in the above embodiments to obtain technical solutions of multiple implementation methods.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An ArF photoresist resin with low edge roughness, characterized in that: ArF photoresist resin is made of the following monomers, and the proportion of each monomer is as follows by weight percentage: 10% to 40% lactone monomer, 20% to 60% acid protection monomer, 0.1% to 20% flexible monomer; The flexible monomer has the following structure: Where: R 13 , R 17 is H or CH3; R 14 , R 15 , R 16 , R 18 , R 20 Same or different, C m H 2m+1 , m is an integer from 0 to 4, R 19 C n H 2n , n is an integer from 0 to 4.

2. The ArF photoresist resin with low edge roughness as claimed in claim 1, characterized in that: The lactone monomer has the following structure: Wherein: R1, R3, R5, R7 are H or CH3; R2, R4, R6, R8 are C x H 2x , x is an integer from 1 to 4.

3. An ArF photoresist resin with low edge roughness as claimed in claims 1 to 2, characterized in that: The acid protection monomer has the following structure: Among them: R9, R 11 is H or CH3; R 10 , R 12 C y H 2y+1 , y is an integer from 0 to 4.

4. The ArF photoresist resin with low edge roughness as claimed in claims 1 to 3, characterized in that: The flexible monomer R 14 , R 15 , R 16 Similarly, preferably, the flexible monomer is butyl acrylate.

5. The ArF photoresist resin with low edge roughness as claimed in claims 1 to 3, characterized in that: The flexible monomer R 18 , R 20 Similarly, preferably, the flexible monomer is hydroxyethyl methacrylate.

6. The ArF photoresist resin with low edge roughness as claimed in claims 1 to 5, characterized in that: The lactone monomer is one of the lactone monomers of the structure. Preferably, the lactone monomer is 2-carboxy-4-bornyl lactone-5-methylacrylate.

7. An ArF photoresist resin with low edge roughness as claimed in claims 1 to 6, characterized in that: The acid-protecting monomer is one of the acid-protecting monomers of the structure. Preferably, the acid-protecting monomer is 2-methyl-2-methylacrylate adamantyl ester.

8. An ArF photoresist resin with low edge roughness as claimed in claims 1 to 6, characterized in that: The ratio of the monomers is: 10% to 40% lactone monomer, 20% to 60% acid protection monomer, 10% to 20% flexible monomer. Preferably, the ratio of the monomers is: 10% to 40% lactone monomer, 20% to 60% acid protection monomer, 15% flexible monomer.

9. A method for preparing an ArF photoresist resin with low edge roughness, characterized in that: The steps include: (1) 10% to 40% of lactone monomer, 20% to 60% of acid protection monomer and 0.1% to 20% of flexible monomer are added into a reactor filled with nitrogen, tetrahydrofuran is added into the reactor, and after stirring evenly, the reactor is heated to 65-67° C., then a tetrahydrofuran solution of azobisisobutyronitrile is added dropwise into the reactor, and the reaction is stirred at 65-67° C. for 3 hours, and then the reaction is stopped and the reactor is cooled to room temperature; the flexible monomer has the following structure: Where: R 13 , R 17 is H or CH3; R 14 , R 15 , R 16 , R 18 , R 20 Same or different, C m H 2m+1 , m is an integer from 0 to 4, R 19 C n H 2n , n is an integer from 0 to 4. (2) adding methanol 10 times the mass of the reaction solution into the reaction kettle cooled to room temperature in step (1) and stirring evenly to produce precipitation for 1 hour to obtain a solid precipitate, which is then placed in a vacuum dryer to obtain an ArF photoresist resin.

10. A photoresist, characterized in that: The photoresist is prepared from the ArF photoresist resin described in claims 1 to 9.

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