Metal-based hybrid photoresist and preparation method thereof

Abstract

The invention discloses a metal-based hybrid photoresist and a preparation method thereof, a metal precursor and a lactone type annular molecule precursor are circularly deposited on the surface of a substrate through a vapor deposition method, and the metal precursor and the lactone type annular molecule precursor react to obtain a metal-based hybrid photoresist film. The metal-based hybrid photoresist comprises a hybrid structure polymer formed by a metal element and a lactone type cyclic molecule and a main chain formed after ring opening of the metal element and the lactone type cyclic molecule, metal precursors such as tetra (dimethylamino) hafnium and a lactone type cyclic molecule precursor are used as raw materials in the preparation process, the cost is low, and special synthesis is not needed. The metal-based hybrid photoresist film is extremely high in surface flatness, excellent in etching selectivity, corrosion resistance and dissolving property and capable of being developed after being exposed and put into water, and the photoresist and the preparation method thereof have wide commercial application prospects and practical value.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor photolithography materials technology, and particularly relates to a metal-based hybrid photoresist and its preparation method. Background Technology

[0002] Extreme ultraviolet (EUV) photoresist is a crucial material in advanced semiconductor manufacturing. Due to the higher photon energy of EUV light sources, the exposure reaction of EUV photoresist becomes primarily radiation-driven. Currently, EUV light sources have relatively low power and photon density, resulting in significant photon shot noise and increased random defects. This also places higher demands on the sensitivity and other properties of the photoresist. Existing organic polymer chemically amplified (CAR) photoresists have revealed a series of problems in use, necessitating improvements or the development of novel photoresists. Novel hybrid resists incorporating metal elements have attracted widespread attention. On one hand, metal atoms such as Sn, Hf, and Zn have higher EUV absorption cross-sections, which can effectively improve EUV utilization and reduce the critical dose required for photoresist exposure. On the other hand, metals can also enhance the etching resistance and mechanical strength of the photoresist film, thereby suppressing pattern collapse. Currently, most newly developed metal-containing photoresists are still wet systems. Because their formulations contain multiple components, component aggregation and segregation are prone to occur during spin coating and pre-baking steps, which increases the randomness of the chemical composition of the photoresist and thus affects the pattern roughness performance.

[0003] Dry photoresist systems primarily rely on vapor deposition methods, such as chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), and molecular layer deposition (MLD). These methods offer advantages in controlling the uniformity of photoresist film composition, and CVD methods are highly compatible with other processes in semiconductor manufacturing, making them easy to integrate. The use of tin-based precursors and water to prepare photoresist films via CVD is currently the only reported photoresist developed based on CVD methods. This preparation system utilizes the difference in reactivity between different groups such as amine and alkyl groups in the tin-based precursor, selectively reacting with water. This allows the less reactive alkyl groups to remain in the final photoresist film as EUV-responsive groups, resulting in excellent resolution. However, this preparation method requires the use of specially synthesized tin-based precursors containing asymmetric groups, leading to high raw material preparation costs. For some existing simple preparation systems, such as photoresists obtained by MLD using hafnium precursors, zirconium precursors, and ethylene glycol, although the resulting photoresists have more uniform composition and easier-to-control film thickness, the metal and ethylene glycol form a long-range network cross-linked structure. This structure is difficult to dissolve physically with solvents and requires high concentrations of hydrochloric acid for development. Therefore, there is an urgent need to develop a low-cost metal-hybrid photoresist with excellent solubility and its preparation method. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a metal-based hybrid photoresist and its preparation method. This invention employs vapor deposition methods such as molecular layer deposition to directly form a dry photoresist film on a single-crystal silicon substrate, avoiding component aggregation and segregation caused by solution preparation and spin-coating processes in wet-process methods. This invention uses metal precursors such as tetra(dimethylamino)hafnium, tetra(ethylmethylamino)hafnium, and tetra(ethylmethylamino)tin, and lactone precursors such as ε-caprolactone, valproic acid lactone, and angelic acid lactone as raw materials. These precursors do not require specialized synthesis, resulting in low cost. The metal-based hybrid photoresist deposited using this invention exhibits excellent solubility and can be developed in water after EUV or electron beam exposure to obtain the corresponding exposure pattern.

[0005] In a first aspect, the present invention discloses a metal-based hybrid photoresist, comprising a hybrid polymer structured by metal atoms and lactone-type cyclic molecules and by metal atoms and the open-ring backbone of lactone-type cyclic molecules. In the photoresist, metal atoms are coordinated with nitrogen, oxygen of lactone-type cyclic molecules and oxygen on the open-ring backbone of lactone-type cyclic molecules, and the molar ratio of metal elements to lactone-type cyclic molecules and the open-ring backbone structure of lactone-type cyclic molecules is 1:2~3.

[0006] Furthermore, the metallic element includes at least one of tin, hafnium, and zirconium.

[0007] Furthermore, the lactone-type cyclic molecule includes at least one of ε-caprolactone, methyl-ε-caprolactone, valproic acid lactone, and angelic acid lactone.

[0008] Furthermore, the photoresist is a negative photoresist used in EUV exposure, electron beam exposure, ion beam exposure, and X-ray exposure.

[0009] Secondly, the present invention also discloses a method for preparing a metal-based hybrid photoresist, comprising: cyclically depositing a metal precursor and a lactone-type cyclic molecular precursor on a substrate surface by a vapor deposition method, and reacting the metal precursor and the lactone-type cyclic molecular precursor to obtain a metal-based hybrid photoresist film.

[0010] Furthermore, the vapor deposition method includes CVD, PECVD, ALD, or MLD.

[0011] Furthermore, the metal precursor includes at least one of tetra(dimethylamino)hafnium, tetra(ethylmethylamino)hafnium, tetra(dimethylamino)tin, tetra(ethylmethylamino)tin, tetra(dimethylamino)zirconium, and tetra(ethylmethylamino)zirconium.

[0012] Furthermore, the lactone-type cyclic molecular precursor includes at least one of ε-caprolactone, methyl-ε-caprolactone, valproic acid lactone, and angelic acid lactone.

[0013] Furthermore, the thickness of the photoresist film is 5~200nm.

[0014] Furthermore, a metal precursor, a purge gas, and a lactone-type cyclic molecular precursor are sequentially introduced in a pulse-purge manner, and the pulse-purge is performed alternately in a cycle to deposit the metal precursor and the lactone-type cyclic molecular precursor in a cyclic manner. The pulse time for the metal precursor is 0.1~2s, the pulse time for the lactone-type cyclic molecular precursor is 0.5~10s, and the purge time for the purge gas is 5~100s.

[0015] Furthermore, the photoresist film deposition temperature is 50~200℃.

[0016] This invention provides a metal-based hybrid photoresist and its preparation method. Compared with the prior art, this invention has at least the following advantages: (1) The present invention creatively uses metal precursors such as tetra(dimethylamino)hafnium and tetra(ethylmethylamino)hafnium and lactone-type cyclic molecular precursors as raw materials. The precursors do not need to be specially synthesized and the raw material cost is low, which makes the photoresist and its preparation method of the present invention have broad commercial application prospects.

[0017] (2) The metal-based hybrid photoresist of the present invention has excellent solubility. After exposure by EUV or electron beam, it can be developed in water and the corresponding exposure pattern can be obtained. The development process does not require the use of acid or organic solvents, which not only further reduces the cost of photoresist preparation, but also simplifies the photoresist preparation process. It is easy to integrate with other steps in the photoresist preparation process, further enhancing the commercial application value of the present invention.

[0018] (3) The metal-based hybrid photoresist film of the present invention has extremely high surface flatness and surface roughness of only about 0.75 nm. Moreover, it has extremely excellent etching selectivity and resolution, with etching selectivity reaching 10 and single exposure resolution reaching 50 nm. The above comprehensive performance ensures that the photoresist of the present invention has good commercial value and application potential. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the microstructure of the metal-based hybrid photoresist of the present invention; Figure 2 This is a schematic diagram of the deposition, exposure, and development process of the metal-based hybrid photoresist of the present invention; Figure 3 This is a microscopic surface morphology image of the hafnium-caprolactone photoresist film in Example 1 of the present invention, wherein... Figure 3 (Left) Surface morphology image characterized by scanning electron microscopy (SEM). Figure 3 (Right) Surface morphology image characterized by atomic force microscopy (AFM); Figure 4 These are infrared characterization spectra of metal-based hybrid photoresist films in various embodiments of the present invention; Figure 5 This is a surface morphology image characterized by an optical microscope after electron beam exposure and development of a hafnium-caprolactone photoresist film with a 5 μm linewidth and equal spacing pattern in Experimental Example 1 of this invention. Figure 5 (Left) Surface morphology image after development in deionized water. Figure 5 (Right) is a surface morphology image after development in 0.1M hydrochloric acid; Figure 6 This is a microscopic surface morphology image of the hafnium-caprolactone photoresist film in Experimental Example 1 of the present invention after electron beam exposure and water development, showing a 5μm linewidth, evenly spaced pattern. Figure 6(Left) Surface morphology image characterized by SEM. Figure 6 (Right) Surface morphology image characterized by AFM; Figure 7 This is a SEM image of the surface morphology of the zirconium-caprolactone photoresist film after electron beam exposure and development according to a 50 nm linewidth pattern, as shown in Experimental Example 2 of this invention. Figure 7 (Left) Surface morphology image after development in deionized water. Figure 7 (Right) is a surface morphology image after development in 0.1M hydrochloric acid; Figure 8 This is a SEM image of the tin-valerol photoresist film in Experimental Example 3 of this invention after electron beam exposure and development according to a 20nm linewidth pattern. Figure 8 (Left) Surface morphology image after development in deionized water. Figure 8 (Right) is a surface morphology image after development in 0.1M hydrochloric acid; Figure 9 This is a comparison image of the exposed and developed pattern before and after etching in Experimental Example 4 of this invention, wherein... Figure 9 (Top left) is an AFM characterization image of the pattern before etching. Figure 9 (Bottom left) is a cross-sectional view of the step height of the pattern before etching. Figure 9 (Top right) is an AFM characterization image of the etched pattern. Figure 9 (Bottom right) is a cross-sectional view of the step height of the etched pattern. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] Unless otherwise specified, all temperatures mentioned herein are in degrees Celsius, and the preferred embodiments can be freely combined as needed. Those skilled in the art will understand that the data and parameters described in the examples are merely exemplary and do not constitute a limitation of the invention. All components used in the following examples and comparative examples are compounds known in the art, and all equipment used is equipment publicly known in the art. All components and equipment used in this invention can be obtained commercially or prepared using known techniques.

[0023] This invention provides a metal-based hybrid photoresist, comprising a hybrid polymer structure formed by metal atoms and lactone-type cyclic molecules, and by metal atoms and the open-ring backbone of lactone-type cyclic molecules. In the photoresist, metal atoms are coordinated with nitrogen, oxygen of lactone-type cyclic molecules, and oxygen on the open-ring backbone of lactone-type cyclic molecules. The molar ratio of metal elements to lactone-type cyclic molecules and the open-ring backbone structure of lactone-type cyclic molecules is 1:2~3.

[0024] The metal-based hybrid photoresist of this invention is obtained by reacting a metal precursor with a lactone-type cyclic molecular precursor in a molar ratio of 1:2 to 3. The metal precursor and lactone-type cyclic molecules are alternately deposited on the substrate surface, forming a hybrid polymer containing metal-amide and metal-oxygen-carbon structures through a ring-opening reaction. Simultaneously, because the metal-amide structure undergoes partial hydrolysis in air, the metal-based hybrid photoresist also forms a metal-carboxylate structure within the hybrid polymer upon contact with air.

[0025] In the metal-based hybrid photoresist of this invention, the carbon backbone of the lactone-type cyclic molecules after ring-opening serves as a linking group, connecting metal atoms and playing a role in exposure response. Due to the moderate reactivity of the lactone-type cyclic molecules, some of them do not undergo ring-opening reactions during deposition. These lactone-type cyclic molecule precursors directly bond to metal atoms in a cyclic form within the hybrid film, effectively limiting the size of the three-dimensional covalent network structure within the film, thereby improving the film's solubility. Furthermore, some lactone-type cyclic molecule precursors undergo double reactions with two metal atoms within the same molecular layer after ring-opening. These precursors also help limit the size of the crosslinked network, further enhancing the film's solubility. It is precisely because of the partial non-ring-opening reaction and double reaction of the lactone-type cyclic molecules during deposition that the metal-based hybrid photoresist of this invention exhibits extremely excellent solubility. Therefore, the lactone-type cyclic molecule of the present invention is preferably at least one of ε-caprolactone, methyl-ε-caprolactone, valproic acid lactone, or angelic acid lactone, which can undergo the above-mentioned reaction. Furthermore, the metal core atom has a large energy absorption cross-section, which can improve the utilization rate of extreme ultraviolet or other radiation energy. Therefore, the metal element of the present invention is preferably at least one of tin, hafnium, zirconium, or indium, and the corresponding metal precursor can be tetra(dimethylamino)hafnium or tetra(ethylmethylamino)hafnium, tetra(dimethylamino)tin or tetra(ethylmethylamino)tin, tetra(dimethylamino)zirconium or tetra(ethylmethylamino)zirconium, tetra(dimethylamino)indium or tetra(ethylmethylamino)indium, etc.

[0026] Figure 1The diagram illustrates the microstructure of a metal-based hybrid photoresist formed by vapor deposition of tetra(dimethylamino)hafnium or tetra(ethylmethylamino)hafnium and ε-caprolactone onto a silicon substrate. The structure includes hybrid polymers formed by Hf and caprolactone, and Hf and the open-ring backbone of caprolactone. Hf coordinates with N, the oxygen atom of caprolactone, and the oxygen atom on the carbon backbone after the caprolactone ring-opening, thus forming hafnium-amide and hafnium-oxygen-carbon structures. Furthermore, when this metal-based hybrid photoresist comes into contact with air, some of the hafnium-amide structures hydrolyze to form hafnium-carboxylate structures. Additionally, due to the presence of a thin oxide layer on the surface of the silicon substrate, such as single-crystal silicon, the Hf atoms of the initially introduced hafnium-based precursor form covalent bonds with the oxygen atoms at the oxide terminals, thereby depositing a photoresist film on the substrate surface.

[0027] The metal-based hybrid photoresist of this invention can be used as a negative photoresist in EUV exposure, electron beam exposure, ion beam exposure, X-ray exposure and other advanced photolithography processes.

[0028] The present invention also provides a method for preparing a metal-based hybrid photoresist, comprising: cyclically depositing a metal precursor and a lactone-type cyclic molecular precursor on a substrate surface by vapor deposition, and reacting the metal precursor and the lactone-type cyclic molecular precursor to obtain a metal-based hybrid photoresist film.

[0029] The vapor deposition method used in this invention includes CVD, PECVD, ALD or MLD. The vapor deposition method of this invention can directly use precursor gas to form a film without the need for the solution preparation and spin coating operations in wet film formation processes, which are prone to component aggregation and segregation.

[0030] The preparation method of the metal-based hybrid photoresist of the present invention specifically includes the following steps: S1. Preprocessing The substrate is ultrasonically cleaned in deionized water and then dried with high-purity nitrogen or argon to remove surface particles, dust and other contaminants. S2. Preheating The pretreated substrate is placed in the deposition chamber of the vapor deposition equipment, the deposition chamber is heated and maintained at the target deposition temperature, and the precursor is heated to the target temperature. S3. Deposition A metal precursor, purge gas, and a lactone-type cyclic molecular precursor, along with purge gas, are sequentially introduced into the deposition chamber using a pulse-purge method. Each precursor undergoes one pulse-purge cycle, constituting one deposition cycle. Multiple deposition cycles are performed, alternatingly depositing the metal precursor and the lactone-type cyclic molecular precursor on the substrate surface to grow a metal-based hybrid photoresist film. During the deposition cycle, the metal precursor and the lactone-type cyclic molecular precursor react to form a molecular structure in which metal atoms are interconnected with the lactone-type cyclic molecular backbone.

[0031] To improve the utilization rate of photoresist to extreme ultraviolet or other radiation energy, the metal precursor of this invention preferably has a high energy absorption atomic cross section, such as tetra(dimethylamino)hafnium, tetra(ethylmethylamino)hafnium, tetra(dimethylamino)tin, tetra(ethylmethylamino)tin, tetra(dimethylamino)zirconium, tetra(ethylmethylamino)zirconium, etc. The metal precursors used in this invention not only have high energy utilization but are also inexpensive and do not require special synthesis. The chemical structural formulas of each metal precursor are shown below: , .

[0032] To improve the solubility of photoresist, this invention preferably uses lactone-type cyclic precursors as organic ligands, such as ε-caprolactone, methyl-ε-caprolactone, valproic acid lactone, and angelicin. The lactone-type cyclic precursors used in this invention possess moderate reactivity, capable of undergoing incomplete ring-opening reactions and double reactions, effectively limiting the size of the three-dimensional covalent network structure within the photoresist film, thereby improving the solubility of the photoresist film. Based on this, the photoresist of this invention can be developed and the corresponding exposure pattern obtained by immersing it in water after EUV or electron beam exposure, without the need for acid or organic solvents in the development process. The chemical structural formulas of each lactone-type cyclic precursor are shown below: .

[0033] The thickness of the photoresist film of the present invention is determined by the number of deposition cycles of the two precursors. The number of deposition cycles in the vapor deposition process can be determined according to the required film thickness. The thickness of the photoresist film of the present invention is preferably 5~200nm, more preferably 10~200nm.

[0034] Depending on the substrate type and precursor type, the precursor pulse time and deposition temperature during the deposition cycle will vary considerably and can be specifically set according to the substrate type, precursor type, and their reaction conditions. For semiconductor silicon wafers or other substrates requiring planar patterning processes, and for the metal precursor and lactone-type cyclic molecular precursor used in this invention, the preferred pulse time for the metal precursor is 0.1~2s, the preferred pulse time for the lactone-type cyclic molecular precursor is 0.5~10s, the preferred purge gas purging time is 5~100s, and the preferred photoresist film deposition temperature is 50~200℃.

[0035] The photoresist obtained by the metal-based hybrid photoresist preparation method of the present invention is a negative photoresist, that is, the exposed area retains a thin film after development. Figure 2 The diagram illustrates the process flow of this invention for preparing a metal-based hybrid photoresist film via vapor deposition, followed by EUV exposure and development. After exposure, the metal-based hybrid photoresist of this invention can be developed using a water-treated substrate sample to obtain the target pattern.

[0036] The present invention will now be described in more detail with reference to exemplary embodiments. The following embodiments or experimental data are intended to illustrate the present invention by way of example, and those skilled in the art should understand that the present invention is not limited to these embodiments or experimental data.

[0037] Example 1 Hafnium-ε-caprolactone photoresist was prepared by molecular layer deposition using tetra(dimethylamino)hafnium and ε-caprolactone, including the following steps: S1. Preprocessing The substrate is an N-type arsenic-doped silicon substrate with an area of ​​1×1cm. -2 The resistivity is 0.001~0.005Ω·cm; the substrate is ultrasonically cleaned in deionized water for 5 minutes, and then the substrate is purged with high-purity nitrogen to make its surface completely dry. S2. Preheating The substrate was transferred to the deposition chamber of the molecular layer deposition system and preheated for 15 minutes. The chamber was then heated to 100°C and maintained at the target deposition temperature. The carrier gas for the molecular layer deposition system was argon, with a total flow rate of 160 sccm and a chamber pressure of approximately 80 Pa. Tetra(dimethylamino)hafnium was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle heating temperature was maintained at 70°C. ε-caprolactone was also stored in a purge-type source bottle made of 316 stainless steel, and the source bottle heating temperature was maintained at 80°C. S3. Deposition After preheating, deposition can begin. The final film thickness is controlled by the number of deposition cycles. One cycle includes a tetra(dimethylamino)hafnium pulse of 0.5s, argon purging for 25s, ε-caprolactone pulse of 2s, and argon purging for 25s. After 150 deposition cycles, a hafnium-ε-caprolactone film with a thickness of about 10nm is obtained.

[0038] X-ray photoelectron spectroscopy (XPS) analysis was performed on the hafnium-ε-caprolactone thin film deposited in this embodiment. The proportions of each element in the hafnium-ε-caprolactone thin film are shown in Table 1. The atomic number of the metal element hafnium is about 3.87%, and the atomic number of the carbon element is about 63.85%. Since both the cyclic ε-caprolactone molecule and the main chain structure after the ring-opening of the ε-caprolactone molecule in the hafnium-ε-caprolactone thin film contain 6 carbon atoms, the molar ratio of the metal element hafnium to the cyclic ε-caprolactone molecule and the main chain structure after the ring-opening of the ε-caprolactone molecule in the film can be calculated to be about 1:2.75.

[0039] Table 1. XPS results of hafnium-caprolactone films

[0040] Figure 3 This is a microscopic surface morphology image of the metal-based hybrid photoresist film in this embodiment, wherein... Figure 3 (Left) Surface morphology image under SEM characterization; Figure 3 (Right) Surface morphology image characterized by AFM. Figure 3 (Left) As can be seen, the surface of this thin film sample has extremely high smoothness and almost no morphological features. From... Figure 3 As shown on the right, the roughness Ra of the thin film sample in the scanning area is only about 0.75 nm, indicating that a uniform and flat metal-organic hybrid thin film can be obtained by the molecular layer deposition method of this embodiment.

[0041] Example 2 Zirconium-methyl-ε-caprolactone photoresist was prepared by molecular layer deposition using tetra(ethylmethylamino)zirconium and methyl-ε-caprolactone, including the following steps: S1. Preprocessing The substrate is an N-type arsenic-doped silicon substrate with an area of ​​1×1cm. -2 The resistivity is 0.001~0.005Ω·cm; the substrate is ultrasonically cleaned in deionized water for 5 minutes, and then the substrate is purged with high-purity nitrogen to make its surface completely dry. S2. Preheating The substrate was transferred to the deposition chamber of the molecular layer deposition system and preheated for 15 minutes. The chamber was then heated to 80°C and maintained at the target deposition temperature. The carrier gas for the molecular layer deposition system was argon, with a total flow rate of 160 sccm and a chamber pressure of approximately 80 Pa. Tetra(ethylmethylamino)zirconium was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle temperature was maintained at 80°C. Methyl-ε-caprolactone was also stored in a purge-type source bottle made of 316 stainless steel, and the source bottle temperature was maintained at 80°C. S3. Deposition After preheating, deposition can begin. The final film thickness is controlled by the number of deposition cycles. One cycle includes a 1s tetra(ethylmethylamino)zirconia pulse, 25s argon purging, a 2s methyl-ε-caprolactone pulse, and 25s argon purging. After 900 deposition cycles, a zirconium-methyl-ε-caprolactone film with a thickness of approximately 180nm is obtained.

[0042] Example 3 The preparation of tin-valerol photoresist using tetra(dimethylamino)tin and valerol via molecular layer deposition includes the following steps: S1. Preprocessing The substrate is an N-type arsenic-doped silicon substrate with an area of ​​1×1cm. -2 The resistivity is 0.001~0.005Ω·cm; the substrate is ultrasonically cleaned in deionized water for 5 minutes, and then the substrate is purged with high-purity nitrogen to make its surface completely dry. S2. Preheating The substrate was transferred into the deposition chamber of the molecular layer deposition system and preheated for 15 minutes. The chamber was then heated to 60°C and maintained at the target deposition temperature. The carrier gas for the molecular layer deposition system was argon, with a total flow rate of 160 sccm and a chamber pressure of approximately 80 Pa. Tetra(dimethylamino)tin was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle temperature was maintained at 50°C. Valprolactone was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle temperature was maintained at 60°C. S3. Deposition After preheating, deposition can begin. The final film thickness is controlled by the number of deposition cycles. One cycle includes a 2s tetra(dimethylamino)tin pulse, a 50s argon purge, an 8s valproic acid pulse, and a 100s argon purge. After 300 deposition cycles, a tin-valproic acid film with a thickness of approximately 120nm is obtained.

[0043] Example 4 Tin-angelicone photoresist was prepared by molecular layer deposition using tetra(ethylmethylamino)tin and angelicone, including the following steps: S1. Preprocessing The substrate is an N-type arsenic-doped silicon substrate with an area of ​​1×1cm.-2 The resistivity is 0.001~0.005Ω·cm; the substrate is ultrasonically cleaned in deionized water for 5 minutes, and then the substrate is purged with high-purity nitrogen to make its surface completely dry. S2. Preheating The substrate was transferred into the deposition chamber of the molecular layer deposition system and preheated for 30 minutes. The chamber was then heated to 160°C and maintained at the target deposition temperature. The carrier gas for the molecular layer deposition system was argon, with a total flow rate of 160 sccm and a chamber pressure of approximately 80 Pa. Tetra(ethylmethylamino)tin was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle heating temperature was maintained at 100°C. Angelica lactone was stored in a purge-type source bottle made of 316 stainless steel, and the source bottle heating temperature was maintained at 120°C. S3. Deposition After preheating, deposition can begin. The final film thickness is controlled by the number of deposition cycles. One cycle includes a 2s tetra(ethylmethylamino)tin pulse, a 50s argon purge, an 8s angelicin pulse, and a 100s argon purge. After 900 deposition cycles, a tin-angelicin film with a thickness of approximately 25nm is obtained.

[0044] Figure 4 The figures shown are infrared characterization spectra of the metal-based hybrid photoresist films prepared in Examples 1-4. Figure 4 The four infrared spectra, from top to bottom, represent the infrared spectra of the tin-angelicone film in Example 4, the hafnium-ε-caprolactone film in Example 1, the zirconium-methyl-ε-caprolactone film in Example 2, and the tin-valerol film in Example 3. Figure 4 As shown, 1710cm -1 The characteristic peaks near the wavenumber indicate that the films in each embodiment contain unopened lactone-type cyclic molecules that coordinate only with metal atoms. These unopened lactone-type cyclic molecules coordinate with metal atoms through oxygen; 1630 cm⁻¹ -1 The characteristic peaks near the wavenumber indicate that the films in each embodiment contain a metal-amide structure, suggesting that a portion of the open-ring lactone-type cyclic molecular backbone in the photoresist film is coordinated with metal atoms through nitrogen; 1560 cm⁻¹ -1 and 1400 cm -1 The characteristic peaks near the wavenumber indicate that the films in each embodiment contain a metal-carboxylate structure, thus demonstrating that the open-ring lactone-type cyclic molecular backbone in the photoresist film is coordinated with the metal atoms through the oxygen of the carboxylate group; 1130 cm⁻¹ -1 The characteristic peaks near the wavenumber indicate that the films in each embodiment contain a metal-oxygen-carbon structure, which shows that the open-ring lactone-type cyclic molecular backbone is coordinated with the metal atoms through oxygen.

[0045] Exposure test experiment Experimental Example 1 The hafnium-caprolactone sample prepared in Example 1 was exposed using an electron beam, and the exposure pattern was an equally spaced pattern with a linewidth of 5 micrometers.

[0046] The electron beam exposure experiment steps are as follows: S1. Exposure Two hafnium-caprolactone samples from Example 1 were transferred into an electron beam lithography system (TESCANVEGA3, equipped with a pattern generator); the electron beam accelerating voltage was set to 20 kV, the electron beam current to 1 nA, and the electron beam dose to 1000 μC·cm⁻¹. -2 Two samples were subjected to electron beam exposure with a 5-micrometer linewidth and equal spacing pattern. S2. Development The electron beam-exposed sample was placed on a hot stage and baked at 80°C for 3 minutes. The two samples were then developed in deionized water for 1 minute and in 0.1M hydrochloric acid for 30 seconds to obtain the target pattern.

[0047] Figure 5 The image shown is a microscopic surface morphology image characterized by an optical microscope after electron beam exposure and development of an equally spaced pattern with a linewidth of 5 micrometers on the surface of the thin film in this experimental example. Figure 5 (Left) shows the surface morphology after development in deionized water. Figure 5 (Right) shows the surface morphology after development in 0.1M hydrochloric acid. Figure 5 It can be seen that the hafnium-caprolactone thin film sample of Example 1 has a clearly defined target pattern under both development conditions, indicating that the metal-based hybrid photoresist of the present invention can be developed using water, and the clarity achieved by developing with deionized water is equivalent to that achieved by developing with acid. Furthermore, Figure 5 The presence of a thin film (light-colored area) in the middle exposure area indicates that the hafnium-caprolactone photoresist prepared in Example 1 is a negative photoresist.

[0048] Figure 6 The image shown is a microscopic surface morphology of the 5-micrometer linewidth equidistant pattern on the thin film surface in this experimental example after electron beam exposure and water development. Figure 6 (Left) is a surface morphology image characterized by SEM. Figure 6 (Right) Surface morphology image characterized by AFM. Figure 6 It can be seen that the target pattern obtained after water development has very regular 5-micrometer linewidth equally spaced stripes, and the boundaries are extremely clear and fine. Figure 6 Both characterization results indicate that hafnium-caprolactone photoresist has excellent electron beam exposure response and water development capability, and possesses extremely high commercial application potential and practical value.

[0049] Experiment Example 2 The zirconium-caprolactone sample prepared in Example 2 was exposed using an electron beam, and the exposure pattern was an evenly spaced pattern with a linewidth of 50 nm.

[0050] The electron beam exposure experiment steps are as follows: S1. Exposure Two zirconium-caprolactone samples from Example 2 were transferred into an electron beam lithography system, the same as in Example 1; the electron beam accelerating voltage was set to 30 kV, the electron beam current to 0.1 nA, and the electron beam dose to 1400 μC·cm⁻¹. -2 Two samples were subjected to electron beam exposure with equidistant patterns of 50nm linewidth. S2. Development The electron beam exposed sample was placed on a hot stage and baked at 80°C for 3 min. Two samples with a linewidth of 50 nm were developed in deionized water for 1 min and in 0.1 M hydrochloric acid for 30 s to obtain the target pattern.

[0051] Figure 7 The image shown is a SEM image of a 50 nm linewidth pattern after electron beam exposure and development. Figure 7 (Left) Surface morphology image after development in deionized water. Figure 7 (Right) is a surface morphology image after development in 0.1M hydrochloric acid. As can be seen, the zirconium-caprolactone sample prepared in Example 2 has a clear and regular target pattern under both development conditions, indicating that the metal-based hybrid photoresist of the present invention can be developed using water, and the clarity achieved by developing with deionized water is equivalent to that achieved by developing with acid.

[0052] Experimental Example 3 The tin-valerol sample prepared in Example 3 was exposed using an electron beam, and the exposure pattern was an evenly spaced pattern with a linewidth of 20 nm.

[0053] The electron beam exposure experiment steps are as follows: S1. Exposure Two tin-valerol samples from Example 3 were transferred into an electron beam lithography system, the same as in Example 1; the electron beam accelerating voltage was set to 30 kV, the electron beam current to 0.1 nA, and the electron beam dose to 1400 μC·cm⁻¹. -2 Two samples were subjected to electron beam exposure with a 20nm linewidth and equal spacing pattern. S2. Development The electron beam exposed sample was placed on a hot stage and baked at 80°C for 3 min. Two samples with a linewidth of 20 nm were developed in deionized water for 1 min and in 0.1 M hydrochloric acid for 30 s to obtain the target pattern.

[0054] Figure 8 The image shown is a SEM image of a 20 nm linewidth pattern after electron beam exposure and development. Figure 8 (Left) Surface morphology image after development in deionized water. Figure 8 (Right) is a surface morphology image after development in 0.1M hydrochloric acid. It can be seen that even for fine patterns with a linewidth of 20nm, the tin-valerol sample prepared in Example 3 can form relatively clear and regular target patterns under both development conditions, indicating that the metal-based hybrid photoresist of the present invention can be developed using water, and the clarity achieved by developing with deionized water is equivalent to that achieved by developing with acid. Figure 7 and Figure 8 The SEM characterization results all show that the metal-based hybrid photoresist of the present invention has extremely excellent electron beam exposure response and water development capability, and has extremely high commercial application potential and practical value.

[0055] Etching test experiment Experiment Example 4 The etching test of the hafnium-caprolactone sample after water development in Experimental Example 1 was performed using capacitive-inductively coupled plasma (ICP-CCP) to confirm the etching selectivity of the metal-based hybrid photoresist of the present invention.

[0056] The ICP-CCP etching experiment steps are as follows: AFM testing was performed on the hafnium-caprolactone sample pattern after water development. Figure 9 (Top left) and Figure 9 (Lower left) It can be seen that the height of the pattern before etching is about 10nm; After developing with water, place the hafnium-caprolactone sample on the sample stage inside the ICP-CCP equipment chamber. Evacuate the equipment chamber to a vacuum level of less than 5 Pa. Turn on the carrier gas and introduce argon at a flow rate of 5 sccm, carbon tetrafluoride at a flow rate of 35 sccm, and oxygen at a flow rate of 10 sccm. After the flow rate stabilizes, maintain the chamber pressure at approximately 35 Pa. Turn on the plasma generator of the ICP-CCP equipment, with the ICP generator power set to 400W and the CCP generator power set to 150W, and etch the hafnium-caprolactone sample for 5 minutes; The etched sample was removed, and the pattern height was measured using AFM. Figure 9 (top right) and Figure 9(Bottom right) It can be seen that the pattern height after etching is approximately 100 nm. Based on the pattern height before and after etching, it can be found that the etching selectivity of the hafnium-caprolactone sample compared to the silicon substrate is approximately 10. This indicates that the metal-based hybrid photoresist of the present invention has excellent etching selectivity and etching resistance.

[0057] All materials used in this invention are commercially available and can be purchased from retail sources.

[0058] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A metal-based hybrid photoresist, characterized in that, The photoresist comprises a hybrid polymer structure formed by metal atoms and lactone-type cyclic molecules, and by metal atoms and the open-ring backbone of lactone-type cyclic molecules. In the photoresist, metal atoms are coordinated with nitrogen, oxygen of lactone-type cyclic molecules, and oxygen on the open-ring backbone of lactone-type cyclic molecules. The molar ratio of metal elements to lactone-type cyclic molecules and the open-ring backbone structure of lactone-type cyclic molecules is 1:2~3.

2. The metal-based hybrid photoresist according to claim 1, characterized in that, The metallic element includes at least one of tin, hafnium, and zirconium.

3. The metal-based hybrid photoresist according to claim 1, characterized in that, The lactone-type cyclic molecule includes at least one of ε-caprolactone, methyl-ε-caprolactone, valerolactone, and angelolactone.

4. The metal-based hybrid photoresist according to claim 1, characterized in that, The photoresist is a negative photoresist used in EUV exposure, electron beam exposure, ion beam exposure, and X-ray exposure.

5. A method for preparing a metal-based hybrid photoresist, characterized in that, The preparation method includes: cyclically depositing a metal precursor and a lactone-type cyclic molecular precursor on the substrate surface by vapor deposition, and reacting the metal precursor and the lactone-type cyclic molecular precursor to obtain a metal-based hybrid photoresist film.

6. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The vapor deposition method includes CVD, PECVD, ALD, or MLD.

7. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The metal precursor includes at least one of tetra(dimethylamino)hafnium, tetra(ethylmethylamino)hafnium, tetra(dimethylamino)tin, tetra(ethylmethylamino)tin, tetra(dimethylamino)zirconium, and tetra(ethylmethylamino)zirconium.

8. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The lactone-type cyclic molecular precursor includes at least one of ε-caprolactone, methyl-ε-caprolactone, valproic acid lactone, and angelic acid lactone.

9. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The thickness of the photoresist film is 5~200nm.

10. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The metal precursor, purge gas, and lactone-type cyclic molecular precursor are sequentially introduced in a pulse-purge manner, and the pulse-purge is repeated in a cycle to deposit the metal precursor and lactone-type cyclic molecular precursor. The pulse time for the metal precursor is 0.1~2s, the pulse time for the lactone-type cyclic molecular precursor is 0.5~10s, and the purge time for the purge gas is 5~100s.

11. The method for preparing the metal-based hybrid photoresist according to claim 5, characterized in that, The deposition temperature of the photoresist film is 50~200℃.

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