Fluorine-containing tin-oxo cluster photoresist compound and use thereof in photoetching field

Abstract

The present invention relates to a fluorine-containing tin-oxo cluster compound and a use thereof. The introduction of fluorine into the fluorine-containing tin-oxo cluster compound enhances the chemical stability of a photoresist material, reduces chemical degradation possibly occurring during storage and use, and contributes to high-precision and high-resolution pattern transfer, thereby improving the performance and reliability of a semiconductor device. In addition, the photoresist compound has excellent solubility and film-forming property, so that a high-quality film is formed on a silicon wafer. The photoresist compound can be applied to the fields of electron beam lithography, deep ultraviolet lithography, extreme ultraviolet lithography, etc. In these applications, the photoresist can provide a high-resolution, low-LER-value and accurate pattern transfer capability, meeting the requirements of microelectronic manufacturing processes. In conclusion, the present invention provides a synthesized fluorine-containing tin-oxo cluster compound, which has high thermal stability, storage stability, solubility, and film-forming property, is suitable for various lithography techniques, and has important application value in the field of microelectronic manufacturing.

Description

A class of fluorinated tin oxide cluster photoresist compounds and their applications in photolithography Technical Field

[0001] This invention relates to the field of photolithography materials, specifically to a class of fluorine-containing tin oxide cluster photoresist compounds and their applications in the field of photolithography. Background Technology

[0002] Photolithography plays a crucial role in microelectronics manufacturing, serving as a key step in the fabrication of high-performance electronic devices. Photoresist is an indispensable material in the photolithography process, enabling the transfer of patterns under illumination and the formation of desired structures on the surface of semiconductor materials. However, traditional photoresists still present some challenges in applications requiring high resolution, high precision, and high performance.

[0003] In recent years, research on metal-based extreme ultraviolet (EUV) photoresists has attracted increasing attention. Compared with traditional organic photoresists, metal-based EUV photoresists have unique advantages. First, metal-based EUV photoresists have higher photosensitivity, enabling higher resolution and faster exposure speeds. Second, during the photolithography process, metal-based EUV photoresists can form highly conductive metallic patterns, which helps improve the performance of electronic devices.

[0004] However, current research on metal-based extreme ultraviolet (EUV) photoresists still faces several challenges and limitations. One is the complex synthesis process and the difficulty in obtaining raw materials, leading to high costs. Furthermore, some metal-based UV photoresists exhibit thermal instability and storage stability issues during use, limiting their widespread application. Therefore, developing a novel metal-based UV photoresist with readily available raw materials, low cost, high thermal and storage stability, good solubility, and film-forming properties has become an important research direction.

[0005] Fluorinated tin oxide cluster photoresist is a novel photolithography material that combines the unique properties of fluorinated compounds and tin oxide clusters, providing a high-performance solution for EUV and electron beam lithography. Tin oxide clusters possess unique electronic structures and chemical reactivity, serving as photosensitive centers to enhance the photosensitivity and selectivity of the photoresist. Furthermore, the introduction of tin oxide clusters helps improve the mechanical properties of the photoresist, increasing its durability and crack resistance during etching. The introduction of tin can also modulate the solubility and adhesion of the photoresist, which is crucial for achieving high-quality lithographic patterns.

[0006] The addition of fluorine provides an additional advantage to photoresists. Fluorine atoms have high electronegativity and low atomic radius, which makes fluorine-containing compounds generally have excellent hydrophobicity and chemical stability, thus enabling finer pattern transfer in EUV and electron beam lithography.

[0007] Against this backdrop, this patent proposes for the first time a fluorinated tin oxide cluster photoresist material with excellent performance. This fluorinated tin oxide cluster photoresist material exhibits high thermal stability and storage stability, maintaining its performance stability under high-temperature conditions. Furthermore, the fluorinated tin oxide cluster photoresist possesses good solubility and film-forming properties, making it suitable for various photolithography technologies such as electron beam lithography, deep ultraviolet lithography, and extreme ultraviolet lithography. Summary of the Invention

[0008] This invention aims to address the limitations of photoresist types and the problems of low sensitivity, low resolution, and high line roughness of existing photoresists, and provides a fluorine-containing photoresist material and its application.

[0009] The photoresist provided by this invention is suitable for electron beam lithography and extreme ultraviolet lithography, and features low exposure dose, high resolution and low LER value, thus having broad application prospects.

[0010] The technical solution of the present invention is as follows: a fluorinated tin oxide cluster compound applicable to the field of photolithography, wherein the general structural formula of the fluorinated tin oxide cluster compound is shown in (I):

[0011]

[0012] Wherein, R1 is n-butyl; R2 is a phenyl group containing at least one substituent.

[0013] The substituent is at least one of fluorine, trifluoromethyl, and difluoromethyl.

[0014] Some specific fluorinated tin oxide cluster compounds, wherein the substituent is at least one of fluorine or trifluoromethyl.

[0015] In some specific fluorinated tin oxide cluster compounds, R2 is independently selected from the following substituents:

[0016]

[0017] Some specific fluorinated tin oxide cluster compounds have the following structures:

[0018]

[0019]

[0020]

[0021] Some specific fluorinated tin oxide cluster compounds have the following structures:

[0022]

[0023]

[0024]

[0025] Some specific fluorinated tin oxide cluster compounds have the following structures:

[0026]

[0027] A photoresist composition comprising at least one of the compounds described above.

[0028] A photoresist composition comprising, by weight, the following components:

[0029] (1) The solvent accounts for 80-99 parts by weight;

[0030] (2) 1 to 20 parts by weight of at least one of the fluorinated tin oxide cluster compounds;

[0031] (3) The dispersant accounts for 0~0.1 parts by weight;

[0032] (4) Other additives account for 0~0.5 parts by weight;

[0033] The solvent includes, but is not limited to, water, alcohols, esters, ethers, cyclic ethers, benzenes, carboxylic acids, and alkanes.

[0034] The dispersant includes, but is not limited to, polyethylene glycol, hydroxyethyl cellulose, and hydroxypropyl cellulose.

[0035] The other additives include photoacids and free radical quenchers.

[0036] Applications of the fluorinated tin oxide cluster compound and the photoresist composition in the field of photoresist.

[0037] The present invention has the following beneficial effects:

[0038] 1. The fluorinated tin oxide cluster compound of the present invention has high thermal stability and storage stability, good solubility and film-forming properties.

[0039] 2. The fluorinated tin oxide cluster compound of the present invention has high absorption of extreme ultraviolet light, and its absorption cross section is 31 times that of carbon. Its sensitivity is higher than that of commercially available polymer photoresists, so as to reduce the exposure dose.

[0040] 3. The introduced fluorine atoms have high electronegativity and low atomic radius, which makes the fluorinated tin oxide cluster compound of the present invention have excellent hydrophobicity and chemical stability, while improving the corrosion resistance of the photoresist and reducing sidewall erosion, thereby achieving finer pattern transfer in EUV and electron beam lithography, and enabling patterned features with linewidths below 20nm.

[0041] Attached Figure Description

[0042] Figure 1 shows the product of Example 1. 1 H NMR spectrum.

[0043] Figure 2 shows the product of Example 2. 1 H NMR spectrum.

[0044] Figure 3 shows the product of Example 3. 1 H NMR spectrum.

[0045] Figure 4 shows the product of Example 4. 1 H NMR spectrum.

[0046] Figure 5 shows the infrared spectrum of the product from Example 1.

[0047] Figure 6 shows the infrared spectrum of the product from Example 2.

[0048] Figure 7 shows the thermal analysis spectra of the products from Examples 1-3.

[0049] Figure 8 is a crystal structure diagram of Example 1.

[0050] Figure 9 is a crystal structure diagram of Example 2.

[0051] Figure 10 is a diagram of the photoresist film in Example 6.

[0052] Figure 11 shows the morphology of the photoresist film in Example 11 under AFM.

[0053] Figure 12 shows the film thickness measurement of the photoresist film in Example 13 under AFM.

[0054] Figure 13 is a morphology data diagram of the photoresist film in Example 14.

[0055] Figure 14 is a scanning electron microscope image of the electron beam lithography pattern of Example 16.

[0056] Figure 15 is a scanning electron microscope image of the deep ultraviolet lithography pattern in Example 18.

[0057] Figure 16 is an atomic force microscope image of the EUV lithography pattern of Example 19.

[0058] Detailed Implementation

[0059] The present invention will be further described below with reference to specific implementation methods. All raw materials used in the embodiments are commercially available. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0060] Example 1

[0061]

[0062] Butylstannic acid (1040 mg, 5 mmol) and p-fluorophenylacetic acid (771 mg, 5 mmol) were added to a 100 ml double-necked flask and stirred to dissolve in 50 ml toluene. The mixture was refluxed under nitrogen protection for 6 h. After filtration, the supernatant was distilled under reduced pressure to obtain a white crude product. The product was then volatilized in dichloromethane and recrystallized to obtain a pure white product, which was named SnOF-1.

[0063] 1 H NMR (600 MHz, Chloroform-d) δ 7.15 (dd, J = 8.4, 5.5 Hz, 12H), 6.92 (t, J = 8.6 Hz, 12H), 3.48 (s, 12H), 1.45 – 1.35 (m, 12H), 1.20 (m, J = 7.4 Hz, 12H), 1.15 – 1.09 (m, 12H), 0.80 (t, J = 7.3 Hz, 18H).

[0064] Elemental analysis (C 72 H 90 F6O 18 Sn6) Theoretical values: C 41.78%; H 4.38%; Test values: C 41.81%; H 4.38%

[0065] Example 2

[0066]

[0067] Butylstannic acid (1040 mg, 5 mmol) and p-trifluoromethylphenylacetic acid (1020 mg, 5 mmol) were added to a 100 ml double-necked flask and stirred to dissolve in 50 ml toluene. The mixture was refluxed under nitrogen protection for 4 h. The mixture was filtered, and the supernatant was distilled under reduced pressure to obtain a white crude product. The crude product was then volatilized in dichloromethane and recrystallized to obtain a pure white product, which was named SnOF-2.

[0068] 1 H NMR (600 MHz, Chloroform-d) δ 7.49 (d, J = 8.1 Hz, 12H), 7.30 (d, J = 8.0 Hz, 12H), 3.56 (s, 12H), 1.42 – 1.33 (m, 12H), 1.19 (h, J = 7.4 Hz, 12H), 1.15 – 1.09 (m, 12H), 0.77 (t, J = 7.4 Hz, 18H).

[0069] Analytical elemental analysis (C 78 H 90 F 18 O 18 Sn6) Theoretical values: C 39.53%; H 3.83%; Test values: C 39.49%; H 3.99%

[0070] Example 3

[0071]

[0072] Butylstannic acid (1040 mg, 5 mmol) and 3,5-bis(trifluoromethyl)phenylacetic acid (1360 mg, 5 mmol) were added to a 100 ml double-necked flask and stirred to dissolve in 50 ml toluene. The mixture was refluxed under nitrogen protection for 5 h. The mixture was filtered, and the supernatant was distilled under reduced pressure to obtain a white crude product. The crude product was then volatilized in dichloromethane and recrystallized to obtain a pure white product, which was named SnOF-3.

[0073] 1 H NMR (600 MHz, Methylene Chloride-d2) δ 7.78 (s, 6H), 7.72 (s, 12H), 3.65 (q, J = 16.1 Hz, 12H), 1.40 – 1.27 (m, 12H), 1.22 – 1.05 (m, 24H), 0.72 (t, J = 7.4 Hz, 18H).

[0074] Elemental analysis (C 84 H 84 F 36 O 18 Sn6) Theoretical values: C 36.32%; H 3.05%; Test values: C 36.21%; H 3.13%.

[0075] Example 4

[0076]

[0077] Butylstannic acid (1040 mg, 5 mmol) and p-bromophenylacetic acid (1080 mg, 5 mmol) were added to a 100 ml double-necked flask and stirred to dissolve in 50 ml toluene. The mixture was refluxed under nitrogen protection for 5 h. The mixture was filtered, and the supernatant was distilled under reduced pressure to obtain a white crude product. The crude product was then volatilized in dichloromethane and recrystallized to obtain a pure white product, which was named SnOBr-1.

[0078] 1H NMR (600 MHz, Chloroform-d) δ 7.37 (d, J = 8.0 Hz, 12H), 7.06 (d, J = 8.1 Hz, 12H), 3.45 (s, 12H), 1.39 (m, J = 8.3, 7.8 Hz, 12H), 1.21 (h, J = 7.3 Hz, 12H), 1.16 – 1.06 (m, 12H), 0.81 (t, J = 7.3 Hz, 18H).

[0079] Elemental analysis (C 84 H 84 Br6O 18 Sn6) Theoretical values: C 35.51%; H 3.73%; Test values: C 35.38%; H 3.80%.

[0080] Example 5

[0081] Thermal analysis was performed on the products SnOF-1, SnOF-2, and SnOF-3.

[0082] Thermal analysis (Switzerland, model TGA / SDTA851e): Under argon atmosphere, the temperature was increased from 50℃ to 800℃ at a rate of 10℃ / min. The thermal analysis curves are shown in Figure 7. As can be seen from the figure, the three molecules exhibit excellent thermal stability. Furthermore, the thermal analysis curves remained unchanged after 3 months of storage.

[0083] Example 6

[0084] To prepare the photoresist film, 10 mg of the fluorinated tin oxide cluster product SnOF-1 was first dissolved in 1 mL of chloroform solution and filtered through a 0.1 µm PTFE membrane to obtain a uniform photoresist solution. A 1 cm × 1 cm silicon wafer was placed on a spin coater, and 25 µl of the photoresist solution was dropped onto the wafer surface using a pipette. The wafer was spin-coated at 3000 r / min for 1 min, and then baked at 100 ℃ for 1 min on a hot plate. The prepared photoresist film is shown in Figure 10.

[0085] Example 7

[0086] To prepare the photoresist film, 10 mg of the fluorinated tin oxide cluster product SnOF-2 was first dissolved in 1 mL of PGMEA and filtered through a 0.1 µm PTFE filter to obtain the photoresist solution. A 1 cm × 1 cm silicon wafer was placed on a spin coater, and 25 µl of the photoresist solution was dropped onto the surface of the silicon wafer using a pipette. The wafer was spin-coated at 3000 r / min for 1 min, and then baked at 100 ℃ for 1 min on a hot plate.

[0087] Example 8

[0088] To prepare the photoresist film, 10 mg of the fluorinated tin oxide cluster product SnOF-3 was first dissolved in 1 mL of PGMEA and filtered through a 0.1 µm PTFE filter to obtain the photoresist solution. A 1 cm × 1 cm silicon wafer was placed on a spin coater, and 25 µl of the photoresist solution was dropped onto the surface of the silicon wafer using a pipette. The wafer was spin-coated at 3000 r / min for 1 min, and then baked at 100 ℃ for 1 min on a hot plate.

[0089] Example 9

[0090] To prepare the photoresist film, 10 mg of the tin oxide cluster product SnOBr-1 was first dissolved in 1 mL of chloroform and filtered through a polytetrafluoroethylene (PTFE) membrane with a pore size of 0.1 µm to obtain the photoresist solution. A 1 cm × 1 cm silicon wafer was placed on a spin coater, and 25 µl of the photoresist solution was dropped onto the surface of the silicon wafer using a pipette. The wafer was spin-coated at 3000 r / min for 1 min, and then baked on a hot plate at 100 ℃ for 1 min.

[0091] Example 10

[0092] Preparation of photoresist films at different spin coating speeds: 25 µl of the photoresist solution prepared in Example 6 was measured using a pipette and spin-coated onto a 1 cm × 1 cm silicon wafer at spin speeds of 1000, 2000, 3000, 4000, and 5000 r / min, respectively.

[0093] Example 11

[0094] To evaluate the quality of the spin-coated photoresist film in Example 6, the surface morphology of the photoresist film was acquired using an atomic force microscope (AFM) (USA, model: Bruker Dimension Icon) in touch mode, with the acquisition area set to 50 μm * 50 μm. The surface morphology images of the photoresist film of Example 6 observed by AFM, including planar and three-dimensional views, are shown in Figure 11. The root mean square roughness (Rq) of the film was measured to be 0.52 nm, indicating that its surface is smooth and flat.

[0095] Example 12

[0096] To evaluate the quality of the spin-coated photoresist films in Examples 7-9, the same method as in Example 11 was used for testing, and the root mean square roughness (Rq) of the films were 0.76 nm, 0.42 nm, and 0.78 nm, respectively.

[0097] Example 13

[0098] Measurement of photoresist film thickness: A scratch method was used. First, a mark was made on the film surface with a sharp blade. Then, the depth of this scratch was characterized using atomic force microscopy (AFM). The AFM thickness measurement of the photoresist film prepared in Example 6 is shown in Figure 12, and its thickness was measured to be approximately 29 nm.

[0099] Example 14

[0100] To measure the changes in film thickness and film roughness with rotational speed, the thin film prepared in Example 10 was measured using an atomic force microscope, and the results are shown in Figure 13.

[0101] Example 15

[0102] Electron beam exposure experiment: Line exposure of the photoresist film of Example 6 was performed using electron beam lithography (EBL) (Raith ELPHY Quantum, Germany). The designed exposure times were 100 nm, 80 nm, 60 nm, 50 nm, and 40 nm. The voltage was 15 kV, and the current was 1 μA. The exposed silicon wafer was immediately developed in 2-heptanone for 30 s and dried with nitrogen. Other suitable developers include cyclopentanone, toluene, n-butyl acetate, and propylene glycol methyl ether acetate.

[0103] Example 16

[0104] The photolithographic pattern of Example 15 was characterized using a field emission scanning electron microscope (HITACHI SU8600) and an atomic force microscope. Lines with periods of 100 nm, 80 nm, 60 nm, 50 nm, and 40 nm, respectively, with linewidths less than 20 nm and line roughness less than 5 nm, were successfully achieved, as shown in Figure 14. This demonstrates that the fluorine tin oxide cluster product SnOF-1 possesses excellent photolithographic properties.

[0105] Table 1. Linewidth and line roughness of photoresist films in Example 6 at different exposure doses (50nm period)

[0106]

[0107] Example 17

[0108] Electron beam exposure experiment: Electron beam exposure experiments were performed on the photoresist films prepared in Examples 7-9 under the same conditions as in Example 15. The exposure was carried out at 9.0 np·cm. -1 At the specified dosages, the linewidths were 16 nm, 17 nm, and 26 nm, and the roughnesses were 3.9 nm, 4.3 nm, and 5.3 nm, respectively. The performance of the SnOBr-1 photoresist films prepared in Example 9 was lower than that of the fluorinated tin oxide cluster photoresist films prepared in Examples 6-8.

[0109] Example 18

[0110] Deep ultraviolet (DUV) exposure experiment: The photomask was placed above the photoresist film of Example 6, and exposed to 254 nm deep UV light for 300 s, developed in 2-heptanone for 1 min, and dried with nitrogen gas. The photolithographic pattern was characterized using a scanning electron microscope, and a micron-scale pattern was obtained, as shown in Figure 15.

[0111] Example 19

[0112] Extreme ultraviolet (EUV) exposure experiment: The photoresist film of Example 6 was photolithographically lithographically patterned using EUV (13.5 nm) interference exposure at an exposure dose of 120 mJ / cm², and the development method was the same as in Example 10. The lithographic pattern was characterized using field emission scanning electron microscopy and atomic force microscopy, yielding lines with a linewidth of approximately 30 nm, as shown in Figure 16. This demonstrates that the fluorine tin oxide cluster product SnOF-1 is suitable for EUV lithography and exhibits excellent performance.

Claims

1. A class of tin-oxygen cluster compounds, characterized in that, The general structural formula is shown in I: ； Wherein, R1 is n-butyl; R2 is an independent phenyl group containing at least one substituent selected from at least one of fluorine, trifluoromethyl, and difluoromethyl.

2. The compound according to claim 1, characterized in that, The substituent is selected from at least one of fluorine and trifluoromethyl.

3. The compound according to claim 1, characterized in that, R2 is independently selected from the following groups: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 4. The compound according to claim 1, characterized in that, It has the following structure: 、 、 、 、 、 、 、 、 、 、 、 、 、 。 5. The compound according to claim 1, characterized in that, It has the following structure: 、 、 、 、 、 、 、 、 。 6. The compound according to claim 1, characterized in that, It has the following structure: 、 、 。 7. A photoresist composition, characterized in that, Includes the compound according to any one of claims 1-6.

8. The composition according to claim 7, characterized in that, It comprises the following components by weight: Solvent: 80~99%; The compound according to any one of claims 1-6: 1~20%; Dispersant: 0~0.1%; Other additives: 0~0.5%.

9. The composition according to claim 8, characterized in that, The solvent is selected from at least one of water, alcohols, esters, ethers, cyclic ethers, benzenes, carboxylic acids, and alkane solvents; the other additives include photoacids and free radical quenchers.

10. The application of the compound according to any one of claims 1-6 in the field of photoresist.

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