Organic-inorganic hybrid thin film and molecular layer deposition method for preparing the same

Abstract

This invention discloses an organic-inorganic hybrid thin film and its molecular layer deposition preparation method, relating to the fields of semiconductor manufacturing and thin film deposition technology. Using tetramethylaminohafnium and methacrylic acid as precursors, this invention employs molecular layer deposition technology to form an amorphous layered network structure of hafnium-carboxylate on the substrate surface through alternating pulse reactions. The film composition is controlled to be 0.2~1.0 by adjusting the precursor pulse time ratio, and the film thickness is precisely controllable from 30~50 nm by controlling the number of deposition cycles. After electron beam exposure and hydrochloric acid development, the resulting thin film can achieve 1:1 dense line patterning with a linewidth of 50 nm. This invention's method has a wide process window, good repeatability, and is compatible with semiconductor process lines, and can be applied to high-resolution photoresists, optoelectronic devices, sensors, and other fields.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor manufacturing processes and thin film deposition technology, specifically to an organic-inorganic hybrid thin film and its molecular layer deposition preparation method. Background Technology

[0002] With the rapid development of the microelectronics and semiconductor industries, the feature size of devices is constantly shrinking, placing increasingly higher demands on the precision, uniformity, and functionalization of thin film materials. Organic-inorganic hybrid materials, possessing the superior properties of both organic and inorganic components—such as photosensitivity and flexibility—show great promise for applications in micro / nano fabrication, optoelectronic devices, and sensors. In particular, organic-inorganic hybrid thin films are attracting significant attention as a research hotspot for next-generation lithography materials in advanced lithography technologies such as extreme ultraviolet (EUVL).

[0003] Traditionally, spin coating is the primary method for preparing organic-inorganic hybrid thin films. However, spin coating has several inherent drawbacks: First, when the required film thickness decreases to the 30-50 nanometer range, the thickness control precision of spin coating becomes difficult to guarantee, resulting in poor thickness uniformity. Second, spin coating struggles to achieve conformal coverage on substrates with high aspect ratio topologies. Furthermore, spin coating has limited control over the chemical composition and component ratios of the film, making it difficult to precisely regulate the molar ratio of organic and inorganic components, thus affecting the final performance of the film. These limitations severely restrict the application of organic-inorganic hybrid thin films in high-precision micro / nano fabrication.

[0004] Atomic layer deposition (ALD), as an advanced thin-film vapor deposition method, achieves atomically precise control of film thickness and excellent step coverage by alternately introducing gaseous precursors and utilizing surface self-limiting reactions. In recent years, molecular layer deposition (MLD), developed based on ALD, has expanded the reactive precursors from inorganic small molecules to organic small molecules, providing a novel approach for preparing structured organic-inorganic hybrid thin films. MLD not only inherits the precise thickness control and conformal coverage advantages of ALD but also endows the film with functional properties such as photocrosslinking or photodepolymerization by introducing organic molecules containing photosensitive groups, showing unique potential in the preparation of patternable thin films. However, current research on the application of MLD technology to prepare hafnium-methacrylic acid hybrid thin films with high-resolution patterning capabilities is still insufficient, and the influence of deposition process parameters on film composition, structure, and final patterning performance needs further investigation.

[0005] Therefore, to address the aforementioned problems, this invention provides an organic-inorganic hybrid thin film and its molecular layer deposition preparation method. Using tetramethylaminohafnium as an inorganic metal precursor and methacrylic acid as an organic olefinic acid precursor, alternating pulses are introduced into a molecular layer deposition apparatus to induce a self-limiting surface reaction. The molar ratio of organic and inorganic components in the thin film is precisely controlled by utilizing the pulse time ratio. Precise control of the thin film thickness is achieved by controlling the number of deposition cycles, thereby forming a hybrid thin film with an amorphous layered network structure on the substrate surface. After exposure and development, this thin film can achieve high-resolution patterning, thus solving the problems of insufficient precision in controlling the composition and thickness of hybrid thin films and limited patterning resolution in existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide an organic-inorganic hybrid thin film and a method for preparing the same by molecular layer deposition, so as to overcome the problems of insufficient control precision of composition and film thickness and limited patterning resolution of organic-inorganic hybrid thin films in the prior art, and to significantly improve the controllability of composition, thickness uniformity and patterning performance of the thin film.

[0007] The objective of this invention is achieved through the following technical solution: An organic-inorganic hybrid thin film is disclosed, wherein the thin film has an amorphous layered network structure and is formed on the substrate surface by reacting inorganic metal precursors and organic olefinic acid molecular precursors as reactants through a molecular layer deposition process. The molar ratio of inorganic metal precursors to organic olefinic acid molecular precursors in the thin film is controlled within the range of 1:1 to 5 by deposition process parameters (inorganic metal precursor is set to 0.2s, corresponding to organic olefinic acid molecular precursor is set to 0.2s to 1.0s). The film thickness is 30 to 50 nm, and after exposure and development, the thin film can form a dense line pattern with a linewidth of 50 nm and a period of 100 nm, wherein the ratio of linewidth to line spacing is 1:1.

[0008] Preferably, the inorganic metal precursor is tetramethylaminohafnium, and the organic acrylic acid precursor is methacrylic acid. Tetramethylaminohafnium exhibits high reactivity and volatility. The dimethylamino group in its molecule can undergo a ligand exchange reaction with the carboxyl group of methacrylic acid to generate the volatile byproduct dimethylamine, while simultaneously forming a hafnium-carboxylate chemical bond, constituting the basic structural unit of the thin film. This reaction proceeds layer by layer on the substrate surface, forming an organic-inorganic hybrid network. Hafnium atoms possess a high extreme ultraviolet (EUV) absorption cross-section, which helps improve the exposure sensitivity of the thin film in the EUV band. The unsaturated double bonds in the methacrylic acid molecule can undergo a cross-linking reaction during exposure, causing a change in the solubility of the thin film in the developer, thereby achieving negative patterning. Furthermore, methacrylic acid contains the polymerization inhibitor MEHQ, which prevents self-polymerization during storage and heating; the heating temperature needs to be controlled below 100°C to maintain stability.

[0009] Preferably, the deposition reaction temperature of the thin film is 80~120℃, wherein the inorganic metal precursor is heated to 60~80℃ and the organic acrylic acid precursor is heated to 60~80℃. This temperature range ensures that the precursor has sufficient vapor pressure for smooth transport to the reaction chamber, while preventing thermal self-polymerization of the organic precursor due to excessively high temperatures. In a specific implementation, the temperature of the tetramethylaminohafnium precursor can be set to 80℃, the heating temperature of methacrylic acid to 65℃, the inlet temperature to 120℃, the reaction chamber temperature to 120℃, and the outlet temperature to 100℃. This combination of temperature parameters ensures that the precursor is stably transported in gaseous form and reacts fully on the substrate surface, while preventing premature polymerization of methacrylic acid in the pipeline, thus ensuring the stability and repeatability of the deposition process.

[0010] Preferably, the patterning performance of the thin film after exposure is tested using an electron beam exposure system, wherein the accelerating voltage of the electron beam exposure system is 50 kV, the electron beam current is 100 pA, and the exposure dose is 50~1000 μC·cm. -2 In practice, electron beam exposure equipment can be used to test the patterning performance of the thin film, with the exposure dose range set to 400-700 μC·cm. -2 The beam current was set to 100 pA. Under this exposure condition, the unsaturated double bonds in the film underwent sufficient cross-linking, and the solubility of the exposed region in the developer was significantly reduced, thereby achieving high-resolution patterning. Experiments showed that dense line patterns with a linewidth of 50 nm could be obtained under optimized conditions, confirming the excellent resolution performance of the film of this invention.

[0011] Preferably, after exposure, the film is immersed in a 3 mol / L hydrochloric acid solution for development for 5 minutes, then rinsed with ultrapure water for 15 seconds, and finally dried with high-purity nitrogen to obtain a negative patterned structure. The hydrochloric acid solution, as the developer, selectively dissolves the film material in unexposed areas while having an extremely low dissolution rate in exposed cross-linked areas, thus achieving high-contrast patterning. The resulting pattern is clear and complete with low edge roughness. The cleaning step effectively removes development residues, preventing them from affecting subsequent processes; nitrogen drying avoids water stains affecting pattern quality, ensuring pattern integrity and cleanliness.

[0012] The present invention also provides a method for preparing the above-mentioned hybrid thin film, comprising the following steps: S1. Inorganic metal precursor as precursor 1 and organic olefinic acid molecular precursor as precursor 2 are placed in a molecular layer deposition device and heated to a set temperature. S2. In the molecular layer deposition equipment, set the pulse introduction time ratio of precursor 1 and precursor 2, and set the number of alternating deposition cycles to allow the two precursors to undergo self-limiting chemical adsorption and reaction on the substrate surface. After the reaction is completed, hybrid films with different compositions and film thicknesses are obtained. S3. Expose the hybrid film obtained in step S2, and then use a developing solution to immerse the exposed film in a developing process to form a patterned structure on the substrate surface.

[0013] Preferably, in step S2, the pulse introduction time ratio is achieved by controlling the single pulse time of the inorganic metal precursor and the organic acrylate precursor, wherein the pulse time ratio of the inorganic metal precursor to the organic acrylate precursor is 1:1 to 5 (the inorganic metal precursor is set to 0.2s, and the corresponding organic acrylate precursor is set to 0.2s to 1.0s); the number of alternating cycles is determined according to the preset film thickness required. In specific implementations, the deposition effect of a pulse time ratio of tetradimethylaminohafnium to methacrylic acid ranging from 1:1 to 1:5 (i.e., an inorganic / organic ratio of 1.0 to 0.2) can be examined, and the film growth per cycle varies under different ratios. By adjusting the pulse time ratio, the molar ratio of hafnium to methacrylic acid in the film can be precisely controlled, thereby regulating the photosensitivity, crosslinking density, and etching resistance of the film. The film formed when the preferred ratio is 1:3 (i.e., the pulse time ratio of inorganic metal precursor to organic olefinic acid precursor is 0.2s:0.6s, or 0.33) exhibits the best patterning performance. A uniform film with a thickness of approximately 30 nm can be obtained after 100 deposition cycles, with a stable growth rate of about 0.3 nm / cycle, indicating that the deposition process conforms to self-limiting growth characteristics and has excellent repeatability.

[0014] Preferably, in step S2, after each pulse injection, an inert gas is used for purging. The inert gas is high-purity nitrogen, and the purging flow rate is set to 20 sccm. The material pipeline of the molecular layer deposition equipment is kept at 100°C. Nitrogen purging can effectively remove unreacted precursors and reaction byproducts (such as dimethylamine) from the reaction chamber, avoiding gas-phase side reactions and chemical vapor deposition effects, and ensuring the purity and uniformity of film growth. Pipeline insulation can prevent precursor vapor from condensing and depositing during transportation, ensuring the accuracy and stability of the precursor injection rate, thereby improving the controllability of film composition and thickness. In specific implementations, the inlet temperature can be set to 120°C and the outlet temperature to 100°C to ensure that the precursor remains in a gaseous state throughout the transportation path.

[0015] Preferably, in step S3, the exposure process is deep ultraviolet light exposure or electron beam exposure; the deep ultraviolet light exposure wavelength is 254 nm, and the exposure dose is 500~700 mJ·cm. -2The electron beam exposure accelerating voltage is 50 kV, the beam current is 100 pA, and the exposure dose is 50~1000 μC·cm. -2 Deep ultraviolet (DUV) exposure is suitable for the rapid fabrication of micron-scale patterns. In this specific implementation, a 254nm DUV lithography machine was used, with the exposure dose set to 600 mJ·cm⁻¹. -2 This method can produce clear micron-level patterns. Electron beam lithography is suitable for high-precision nanoscale patterning, with an accelerating voltage of 50 kV, a beam current of 100 pA, and an exposure dose of 400–600 μC·cm⁻¹. -2 Under these conditions, 1:1 dense line patterns with a linewidth of 50nm can be achieved, exhibiting excellent resolution and pattern fidelity. The two exposure methods are complementary, meeting the micro-nano fabrication needs of different precision requirements.

[0016] Preferably, in the molecular layer deposition process, a complete deposition cycle includes the following sequential steps: pulsed introduction of an inorganic metal precursor, delay, nitrogen purging, pulsed introduction of an organic olefinic acid precursor, delay, and nitrogen purging. This deposition sequence is designed as Dose (tetramethylaminohafnium) / Delay / Purge / Dose (methacrylic acid) / Delay / Purge. This sequence design ensures that the two precursors alternately contact the substrate surface, avoiding gas-phase mixing reactions and fully utilizing the self-limiting growth advantages of molecular layer deposition technology. In each cycle, the precursor molecules chemically adsorb and react with active sites on the substrate surface to form a monolayer-thick film. Excess unreacted precursors and byproducts are removed by the subsequent nitrogen purging step, providing a clean reaction interface for the next cycle of growth.

[0017] Preferably, the substrate is a silicon wafer. In specific implementations, a silicon wafer can be used as the deposition substrate. The surface of the silicon wafer has natural hydroxyl groups or active groups introduced through treatment, which can serve as initiation reaction sites for molecular layer deposition, undergoing ligand exchange reactions with the tetramethylaminohafnium precursor to achieve thin film nucleation and growth. As a standard substrate in the semiconductor industry, silicon wafers have good compatibility with existing process lines, facilitating subsequent photolithography and patterning processes.

[0018] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. This invention prepares organic-inorganic hybrid thin films using molecular layer deposition technology. It utilizes the self-limiting surface reaction characteristics to achieve atomic-level precise control of film thickness and composition. By adjusting the precursor pulse time ratio and the number of deposition cycles, a uniform thin film with a thickness of 30~50nm and adjustable composition is obtained, overcoming the problem of insufficient control precision in traditional spin coating methods.

[0019] 2. This invention uses tetramethylaminohafnium and methacrylic acid as precursors. The two form a stable amorphous layered network structure of hafnium-carboxylate through ligand exchange reaction. It has both the high extreme ultraviolet absorption capacity of hafnium atoms and the photocrosslinking characteristics of methacrylic acid double bonds. After exposure treatment, the solubility changes significantly, realizing negative patterning.

[0020] 3. The hybrid thin film prepared by this invention, after electron beam exposure, is subjected to an accelerating voltage of 50 kV, a beam current of 100 pA, and a temperature range of 50–1000 μC·cm. -2 Under the given dosage conditions, 1:1 dense line patterning with a linewidth of 50nm can be achieved with excellent resolution; at the same time, micron-level patterns can be rapidly prepared using 254nm deep ultraviolet light exposure, meeting the needs of multi-scale processing.

[0021] 4. In the deposition process, this invention uses high-purity nitrogen purging (20 sccm) to remove residual precursors, and keeps the pipeline at 100°C to avoid condensation, thus ensuring the purity and uniformity of the film. For development, the film is soaked in 3 mol / L hydrochloric acid for 5 min, combined with ultrapure water rinsing and nitrogen drying to obtain a clear and complete high-resolution pattern.

[0022] 5. The preparation method of the present invention has a wide process window (deposition temperature 80~120℃), low energy consumption, good repeatability, and is compatible with semiconductor process lines. It can achieve conformal coverage on various substrate surfaces, and the resulting thin film can be applied to high-resolution photoresists, optoelectronic devices, sensors and other fields, with good industrialization prospects. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the molecular layer deposition mechanism of TDMAHf and MAA in Example 1 of the present invention; Figure 2 This is the thin film obtained by deposition 100 times in Example 1 of the present invention; Figure 3 This refers to the growth per cycle of organic-inorganic hybrid thin films under different inorganic metal and organic molecule ratio deposition conditions in Example 2 of the present invention. Figure 4 These are the infrared transmission spectra of organic-inorganic hybrid thin films under different deposition conditions in Example 2 of this invention; Figure 5This refers to the changes in hydrophilicity and hydrophobicity of organic-inorganic hybrid films before and after exposure under different deposition conditions in Example 2 of this invention. Figure 6 This refers to the changes in ultraviolet absorption of organic-inorganic hybrid thin films under different deposition conditions before and after exposure in Example 2 of the present invention. Figure 7 This is the DUV exposure pattern of Embodiment 3 of the present invention when the ratio of inorganic metal to organic molecules is 1 / 3; Figure 8 These are the sensitivity curves of organic-inorganic hybrid thin films under different deposition conditions in Example 4 of this invention; Figure 9 This is the EBL exposure pattern of Example 4 of the present invention when the ratio of inorganic metal to organic molecules is 1 / 3. Detailed Implementation

[0025] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific implementation schemes are now described in detail.

[0026] The present invention will be further described below with reference to embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0027] Example 1 See appendix Figure 1 - Appendix Figure 2 This embodiment provides a method for preparing an organic-inorganic hybrid thin film, the specific steps of which are as follows: S1. Place the silicon wafer substrate in the reaction chamber of the molecular layer deposition equipment, evacuate the reaction chamber and heat it to the deposition temperature of 120°C; heat the inorganic metal precursor tetradimethylaminohafnium to 80°C and the organic olefinic acid molecular precursor methacrylic acid to 65°C; set the inlet temperature to 120°C and the outlet temperature to 100°C.

[0028] S2. Hafnium tetramethylaminopropionic acid vapor and methacrylic acid vapor are alternately and sequentially pulsed into the reaction chamber. The pulse time ratio is controlled at 1:3 (i.e., inorganic / organic pulse time ratio is 0.2s:0.6s). After each pulse, high-purity nitrogen is used for purging at a flow rate of 20 sccm, causing self-limiting chemical adsorption and reaction of the two on the substrate surface, resulting in the layer-by-layer growth of an organic-inorganic hybrid film. A complete deposition cycle includes the following sequential steps: pulsed introduction of hafnium tetramethylaminopropionic acid, delay, nitrogen purging, pulsed introduction of methacrylic acid, delay, and nitrogen purging.

[0029] S3. By controlling the alternation cycle of step S2 to be 100 times, an organic-inorganic hybrid thin film is deposited on the surface of the silicon substrate.

[0030] S4. The silicon wafer with the hybrid thin film deposited on it is subjected to subsequent characterization or exposure processing.

[0031] The organic-inorganic hybrid thin film prepared in this embodiment was tested and found to have a smooth surface after 100 deposition cycles, as shown in the attached figure. Figure 2 As shown in the attached figure. The deposition mechanism of the thin film is as follows. Figure 1 As shown, tetramethylaminohafnium and methacrylic acid undergo a ligand exchange reaction on the substrate surface, growing layer by layer to form an organic-inorganic hybrid network structure.

[0032] Example 2 See appendix Figure 3 - Appendix Figure 6 This embodiment provides a method for preparing organic-inorganic hybrid thin films with different pulse time ratios, and the specific steps are as follows: S1. Place the silicon wafer substrate in the reaction chamber of the molecular layer deposition equipment, evacuate the reaction chamber and heat it to the deposition temperature of 120°C; heat the inorganic metal precursor tetradimethylaminohafnium to 80°C and the organic olefinic acid molecular precursor methacrylic acid to 65°C; set the inlet temperature to 120°C and the outlet temperature to 100°C.

[0033] S2. Hafnium tetramethylaminoacetic acid vapor and methacrylic acid vapor are alternately and sequentially pulsed into the reaction chamber, and the pulse time ratio is controlled to be 1:1, 1:3, and 1:5 (i.e., inorganic / organic pulse time ratios of 0.2s:0.2s, 0.2s:0.6s, and 0.2s:1.0s, respectively). After each pulse, high-purity nitrogen is used for purging at a flow rate of 20 sccm, so that the two undergo self-limiting chemical adsorption and reaction on the substrate surface, and organic-inorganic hybrid films of different compositions are grown layer by layer.

[0034] S3. By controlling the number of alternating cycles in step S2, organic-inorganic hybrid films of different compositions are deposited on the surface of the silicon substrate.

[0035] S4. Characterize and test the silicon wafer on which the hybrid thin film is deposited.

[0036] The organic-inorganic hybrid films with different components prepared in this embodiment were tested, and their growth per cycle is shown in the attached figure. Figure 3 As shown in the attached figure, the infrared transmission spectrum is as follows. Figure 4 As shown in the attached figure, the changes in hydrophilicity and hydrophobicity before and after exposure are as follows. Figure 5 As shown in the attached figure, the changes in ultraviolet absorption before and after exposure are as follows. Figure 6As shown in the figure. The results indicate that the molar ratio of organic and inorganic components in the film can be precisely controlled by adjusting the pulse time ratio, and the film exhibits good photosensitivity.

[0037] Example 3 See appendix Figure 7 This embodiment is based on the above embodiment 2. The similarities with embodiment 2 will not be repeated. The difference between this embodiment and embodiment 2 is that an organic-inorganic hybrid film obtained by depositing tetradimethylaminohafnium:methacrylic acid with a pulse time ratio of 1:3 (i.e., an inorganic / organic pulse time ratio of 0.2s:0.6s) is subjected to deep ultraviolet light exposure treatment.

[0038] In step S4, the silicon wafer with the hybrid thin film deposited is placed on the sample stage of a deep ultraviolet lithography machine, the exposure wavelength is 254 nm, and the exposure dose is set to 600 mJ·cm⁻¹. -2 After exposure, the sample was developed in a 3 mol / L hydrochloric acid solution for 5 minutes, then rinsed in ultrapure water for 15 seconds, and finally dried with dry high-purity nitrogen gas.

[0039] The organic-inorganic hybrid thin film prepared in this embodiment, after being exposed and developed under deep ultraviolet light, yielded a clear micron-scale pattern, as shown in the attached figure. Figure 7 As shown, the thin film of the present invention has good deep ultraviolet light response characteristics.

[0040] Example 4 See appendix Figure 8 - Appendix Figure 9 This embodiment is based on the above embodiment 2. The similarities with embodiment 2 will not be repeated. The difference between this embodiment and embodiment 2 is that the organic-inorganic hybrid films deposited with different pulse time ratios (tetramethylaminohafnium:methacrylic acid = 1:1, 1:3, 1:5) are subjected to electron beam exposure and sensitivity testing.

[0041] In step S4, the silicon wafer with the hybrid thin film deposited is subjected to electron beam exposure. The exposure conditions are: accelerating voltage 50kV, electron beam current 100pA, and exposure dose range set to 0~1200μC·cm. -2 For films with a pulse-to-time ratio of 1:3, further exposure at a dose of 400-700 μC·cm⁻¹ is performed. -2 Fine exposure was performed within the specified range. After exposure, the sample was developed in a 3 mol / L hydrochloric acid solution for 5 minutes, then rinsed in ultrapure water for 15 seconds, and finally dried with dry high-purity nitrogen gas.

[0042] The sensitivity curve of the organic-inorganic hybrid thin film prepared in this embodiment after electron beam exposure and development is shown in the attached figure. Figure 8As shown. Among them, the film with a pulse time ratio of 1:3 was exposed at an exposure dose of 400 μC·cm⁻¹. -2 Under these conditions, a 1:1 dense line pattern with a linewidth of 50nm was obtained, as shown in the attached figure. Figure 9 As shown, it exhibits excellent resolution and pattern fidelity.

[0043] Example 5 This embodiment is based on the above embodiment 1. The similarities with embodiment 1 will not be repeated. The difference between this embodiment and embodiment 1 is that: in step S1, the deposition temperature is set to 80°C, the tetradimethylaminohafnium is heated to 60°C, and the methacrylic acid is heated to 60°C; in step S2, the pulse time ratio of tetradimethylaminohafnium to methacrylic acid is controlled to be 1:3 (i.e., the inorganic / organic pulse time ratio is 0.2s:0.6s), and the deposition cycle is 120 times.

[0044] The organic-inorganic hybrid thin film prepared in this embodiment was tested and found to have uniform thickness and good surface smoothness. After electron beam exposure and development, clear nanoscale patterns can be formed.

[0045] Example 6 This embodiment is based on the above embodiment 1. The similarities with embodiment 1 will not be repeated. The difference between this embodiment and embodiment 1 is that the pulse time ratio of tetradimethylaminohafnium to methacrylic acid in step S2 is controlled at 1:2 (i.e., the inorganic / organic pulse time ratio is 0.2s:0.4s), and the deposition cycle is 90 times.

[0046] The organic-inorganic hybrid thin film prepared in this embodiment was tested and found to have uniform thickness and a smooth surface. After electron beam exposure and development, clear nanoscale patterns can be obtained.

[0047] Comparative Example 1 This comparative example is based on Example 2 above. The similarities with Example 2 will not be repeated. The difference between this comparative example and Example 2 is that the pulse time ratio of tetradimethylaminohafnium to methacrylic acid in step S2 is controlled at 2:1 (i.e., the inorganic / organic pulse time ratio is 0.2s:0.1s).

[0048] The film prepared in this comparative example showed granular protrusions on its surface and poor uniformity upon testing. After electron beam exposure and development, the pattern was blurry and could not form a clear 1:1 dense line pattern.

[0049] Comparative Example 2 This comparative example is based on Example 2 above. The similarities with Example 2 will not be repeated. The difference between this comparative example and Example 2 is that the pulse time ratio of tetradimethylaminohafnium to methacrylic acid in step S2 is controlled at 1:6 (i.e., the inorganic / organic pulse time ratio is 0.2s:1.2s).

[0050] The thin film prepared in this comparative example showed pinhole defects and poor uniformity upon inspection. After electron beam exposure and development, the patterned portion detached, and the linewidth was uneven, failing to meet the requirements for high-precision patterning.

[0051] Comparative Example 3 This comparative example is based on Example 1 above. The similarities with Example 1 will not be repeated. The difference between this comparative example and Example 1 is that the deposition temperature in step S1 is set to 150°C.

[0052] The film prepared in this comparative example was found to be thin and have a rough surface. Analysis revealed that methacrylic acid underwent partial thermal self-polymerization at high temperatures, which hindered the deposition reaction and reduced film quality. A clear pattern could not be formed after exposure and development.

[0053] Comparative Example 4 This comparative example is based on Example 1 above. The similarities with Example 1 will not be repeated. The difference between this comparative example and Example 1 is that nitrogen was not used for purging in step S2, or the purging flow rate was less than 5 sccm.

[0054] The thin film prepared in this comparative example was found to have uneven thickness and a large number of particulate deposits on the surface. This is because unreacted precursors and reaction byproducts were not effectively removed, leading to gas-phase side reactions that disrupted the self-limiting growth characteristics of molecular layer deposition. The pattern quality was poor after exposure and development.

[0055] The organic-inorganic hybrid films prepared in the above embodiments and comparative examples were subjected to performance testing, including film thickness testing, surface morphology observation, growth per cycle calculation, and pattern quality evaluation after exposure and development. The test results are summarized in the table below.

[0056] Table 1

[0057] As shown in Table 1, the organic-inorganic hybrid films prepared in Examples 1 to 6 of this invention all exhibit good surface quality and patterning performance. In Example 4, the film with a pulse-to-time ratio of 1:3 achieved a dense 1:1 line pattern with a linewidth of 50 nm under electron beam exposure, demonstrating optimal sensitivity and resolution. Example 3 confirmed that the films of this invention can obtain clear micron-level patterns under deep ultraviolet light exposure. Examples 5 and 6 demonstrated the wide adaptability and tunability of the process of this invention.

[0058] The pulse time ratios or process parameters of Comparative Examples 1 to 4 exceeded the protection scope of this invention, resulting in a decrease in film surface quality and deterioration in patterning performance, failing to meet the requirements for high-resolution patterning. These comparative data fully demonstrate the rationality and necessity of the parameter ranges such as pulse time ratio of 1:1 to 5 (0.2s:0.2s to 0.2s:1.0s) and deposition temperature of 80 to 120℃ in the technical solution of this invention, as well as the key role of process measures such as nitrogen purging and pipeline insulation in ensuring film quality.

[0059] In summary, this invention successfully prepared organic-inorganic hybrid thin films using molecular layer deposition (MLD) technology, achieving atomic-level precise control over film thickness and composition by utilizing the self-limiting surface reaction characteristics. Using tetramethylaminohafnium and methacrylic acid as precursors, they form a stable hafnium-carboxylate amorphous layered network structure through ligand exchange reactions, possessing both the high extreme ultraviolet absorption capacity of hafnium atoms and the photocrosslinking properties of methacrylic acid double bonds. By adjusting the precursor pulse time ratio of 1:1~5 (0.2s:0.2s~0.2s:1.0s) and the number of deposition cycles, this invention can obtain uniform thin films with a thickness of 30~50nm and adjustable composition. After electron beam exposure, under an accelerating voltage of 50kV, a beam current of 100pA, and a temperature range of 50~1000μC·cm⁻¹, the film can be further processed. -2 Under the given dosage conditions, 1:1 dense line patterning with a linewidth of 50nm can be achieved with excellent resolution. The preparation method of this invention has a wide process window (deposition temperature 80~120℃), low energy consumption, good repeatability, and is compatible with semiconductor process lines. It can achieve conformal coverage on various substrates such as silicon wafers, and the resulting thin film can be applied to high-resolution photoresists, optoelectronic devices, sensors, and other fields, showing good prospects for industrialization.

[0060] The embodiments described above merely illustrate more specific and detailed implementations of the present invention, and should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An organic-inorganic hybrid thin film, characterized in that, The thin film has an amorphous layered network structure and is formed on the substrate surface by reacting inorganic metal precursors and organic olefinic acid molecular precursors as reactants through a molecular layer deposition process. The molar ratio of inorganic metal precursors to organic olefinic acid molecular precursors in the thin film is controlled within the range of 1:1 to 5 by the deposition process parameters. The film thickness is 30 to 50 nm, and after exposure and development, the thin film can form a dense line pattern with a linewidth of 50 nm and a period of 100 nm, wherein the ratio of linewidth to line spacing is 1:

1. The inorganic metal precursor is tetrakis(2-methylamino)hafnium, and the organic olefinic acid precursor is methacrylic acid. After exposure, the film is immersed in a 3 mol / L hydrochloric acid solution for 5 min for development, then washed with ultrapure water for 15 s, and finally dried with dry high-purity nitrogen to obtain a negative patterned structure. The method for preparing the organic-inorganic hybrid thin film by molecular layer deposition includes the following steps: S1. Inorganic metal precursor as precursor 1 and organic olefinic acid molecular precursor as precursor 2 are placed in a molecular layer deposition device and heated to a set temperature. S2. In the molecular layer deposition equipment, set the pulse introduction time ratio of precursor 1 and precursor 2, and set the number of alternating deposition cycles to allow the two precursors to undergo self-limiting chemical adsorption and reaction on the substrate surface. After the reaction is completed, hybrid films with different compositions and film thicknesses are obtained. S3. Expose the hybrid film obtained in step S2, and then use a developing solution to immerse the exposed film in a developing process to form a patterned structure on the substrate surface.

2. The organic-inorganic hybrid thin film according to claim 1, characterized in that, The deposition reaction temperature of the thin film is 80~120℃, wherein the inorganic metal precursor is heated to 60~80℃ and the organic olefin precursor is heated to 60~80℃.

3. The organic-inorganic hybrid thin film according to claim 1, characterized in that, The patterning properties of the thin film after exposure treatment were tested using an electron beam exposure system. The electron beam exposure system had an accelerating voltage of 50 kV, an electron beam current of 100 pA, and an exposure dose of 50–1000 μC·cm⁻¹. -2 .

4. The organic-inorganic hybrid thin film according to claim 1, characterized in that, In step S2, the pulse introduction time ratio is achieved by controlling the single pulse time of the inorganic metal precursor and the organic olefin precursor, wherein the pulse time ratio of the inorganic metal precursor to the organic olefin precursor is 1:1 to 5; the number of alternating cycles is determined according to the preset film thickness of the required film.

5. The organic-inorganic hybrid thin film according to claim 1, characterized in that, In step S2, after each pulse is introduced, an inert gas is used for purging. The inert gas is high-purity nitrogen, and the purging flow rate is set to 20 sccm. The material pipeline of the molecular layer deposition equipment is kept at 100°C.

6. The organic-inorganic hybrid thin film according to claim 1, characterized in that, In step S3, the exposure process is deep ultraviolet light exposure or electron beam exposure; the deep ultraviolet light exposure wavelength is 254 nm, and the exposure dose is 500~700 mJ·cm. -2 The electron beam exposure accelerating voltage is 50 kV, the beam current is 100 pA, and the exposure dose is 50~1000 μC·cm. -2 .

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