CN115407607A - Application of a Class of Zinc Oxygen Cluster Compounds in Photoresist Field - Google Patents

Abstract

The invention discloses an application of a zinc oxide cluster compound in the field of photoresist, wherein the general structural formula of the zinc oxide cluster compound is shown as A; the zinc oxide cluster compound or the composition thereof is used for preparing the photoresist, the integrated photoresist molecule is a photosensitizer and resin, the synthesis method is simple, the raw materials are simple and easy to obtain, the product can be obtained in high yield by one step of reaction, the product is pure, the benzene and the derivative ligand thereof greatly improve the solubility of the zinc oxide cluster in various solvents or developers, especially the molecule of the 4-trifluorophenyl ligand is suitable for most solvents, has strong process compatibility, and is very suitable for preparing photoresist films with different thicknesses of 15-100 nm and uniformity. Any auxiliary agent can be not added in the production, the implementation is convenient, and the cost is greatly reduced. The synthesized photoresist molecules have high thermal stability and storage stability, no precipitation during baking, no easy denaturation during photoetching, good film forming property, low viscosity and the like, and are suitable for different types of lightAnd (4) engraving technology.

Description

Application of a Class of Zinc Oxygen Cluster Compounds in Photoresist Field

technical field

The invention belongs to the field of material/photolithography technology, and in particular relates to the construction and application of a class of photoresist composition with spatially symmetrical zinc-oxygen cluster compound molecules modified by monocarboxylic acid ligands.

Background technique

Photolithography is a key process in the manufacture of integrated circuits. It uses the principle of photochemical reaction to transfer the pattern prepared in advance on the mask to a substrate (wafer), so that selective etching and ion implantation become possible. Photolithography is a key link in the fabrication process of micro-nano devices; whether it is semiconductor devices, optoelectronic devices, or micro/nano-electro-mechanical systems (micro/nano-electro-mechanical systems, M/NEMS) are inseparable from photolithography craft. Especially in ultra-large-scale integrated circuits, it is precisely because of the development of photoresist materials and processes that the devices on integrated circuits can be made smaller and smaller, the integration of chips is getting higher and higher, and the average cost of a single transistor is getting higher and higher. come lower.

Photolithographic materials refer to adhesion-promoting materials, anti-reflective coatings, photoresists, chemical solvents and developers used in photolithography. These materials are mounted on a coating developer and spin-coated or sprayed onto the wafer, depending on the process flow. Among them, the anti-reflection layer is used to absorb or eliminate the reflected light from the wafer substrate and eliminate the standing wave effect. Photoresist is one of the most important components in photoresist materials. It is a kind of thin film material whose chemical structure changes after energy radiation such as beam, electron beam, ion beam or x-ray, resulting in a change in solubility. The photoresist has broad-spectrum sensitivity under such radiation sources, that is, its energy is higher than the bond energy and ionization energy of any component of the photoresist. Therefore, almost all chemical bonds of the photoresist exposed to such radiation sources will be fracture. This property of high-energy radiation is unfavorable to the selection of chemical functional groups, but when the high-energy beam interacts with the photoresist, it does not depend on the molecular structure of the photoresist, but on the capture cross section of the atom, resulting in a large number of low These low-energy electrons further induce the same molecular-level chemical changes as conventional exposure modes.

Structurally, it is a light-sensitive polymer or small molecule. Examples include molecular glass structures with high glass transition temperatures, and metal-containing clusters, complexes, or nanoparticles. Under the irradiation of light of a certain wavelength or radiation, a series of photochemical reactions or radiation chemical reactions occur to change the structure of the photoresist. The structure determines the properties, so that the exposed part and the unexposed part produce a change in solubility in the developer, and the glue is developed and baked to produce a pattern. It is widely used in the microfabrication of integrated circuit semiconductor devices.

其产生的酸浓度梯度影响最后的粗糙度；而非化学放大型光刻胶中，聚合物容易导致分子缠绕现象，因此在光刻胶的设计上，选择小分子作为光刻胶分子，符合未来先进光刻技术的要求。相比于CAR(Chemical amplificationphotoresist)含有光致产酸剂、聚合物、碱性添加剂等多种组分，在实际生产和应用中有较大的优势。With the increasing integration of the semiconductor industry, chemically amplified photoresist will lead to uncontrolled acid diffusion in the resist, according to the formula of Line Edge Roughness of photoresist

The acid concentration gradient produced by it affects the final roughness; in non-chemically amplified photoresists, polymers are easy to cause molecular entanglement, so in the design of photoresists, small molecules are selected as photoresist molecules, which is in line with the future Requirements for advanced lithography techniques. Compared with CAR (Chemical amplification photoresist), which contains photoacid generators, polymers, basic additives and other components, it has greater advantages in actual production and application.

Most of the zinc oxide photoresists that have been reported so far are produced by the sol-gel method (Advanced Materials Interfaces, 2016, 3(19): 1600373.) (Journal of Materials Chemistry C, 2017, 5(10): 2611-2619.) This type of photoresist is a nano-system, without a clear chemical molecular structure, and its large size is not conducive to the advanced photolithography process; the literature published by the Sonia Castellanos research group in the Netherlands (JournalofMicro/Nanolithography, MEMS, and MOEMS ,2019,18(4):043504.), is to indirectly prepare zinc oxide clusters by stirring and replacing ligands. In its structural schematic diagram, it should be composed of 4 metal 6 ligands, but the literature gives the structure as Zn ₄ O ₁₈ C ₃₁ H _37.5 F _4.5 , analyzed as 4 metals, 8.5 ligands, and the ligand ratio is 7:1.5. The author's description and repeated literature experiments show that this preparation method cannot obtain pure products, and the raw materials are rare , high cost, low yield and poor thermal stability. This mixture results in poor batch stability, and the same number of products contains different numbers of reactive groups, resulting in different light doses required for each batch of synthetic products. In its latest work (Fluorine-Rich ZincOxoclusters as Extreme Ultraviolet Photoresists: Chemical Reactions and Lithography Performance[J].ACS Materials Au,2022.), the same ligand ratio is 2.4:2.9:0.8, and the sum is 6.1 close to the target The number of ligands in the structure is 6, but it is still a mixture, and the film-forming property is greatly reduced compared to before.

In view of the good photolithographic properties of zinc oxides, there is a need for a class of zinc oxide molecules with well-defined structures, excellent thermal stability, storage stability and other properties, and a convenient and cost-effective preparation strategy.

Contents of the invention

In order to solve the above technical problems, according to the reference (Inorganica ChimicaActa, 186 (1991) 51-60), the target molecule was directly synthesized in one step using zinc oxide and 4-trifluoromethylbenzoic acid or benzoic acid. Application of a class of zinc-oxygen cluster compounds based on an organic/inorganic hybrid system in the field of photoresist; the general structural formula of the zinc-oxygen cluster compound is shown in A:

Wherein: R is selected from one of the following substituents:

Zinc oxycluster III is often used in the field of catalysis in the prior art, but it cannot be used in the field of photoresist due to its limited solubility. The zinc-oxygen cluster compounds I and II of the present invention are analogs of the smallest structural unit of the MOF-5 structure, which are rarely used in the prior art. The present invention innovatively applies them in the field of photoresist, which belongs to a new application . It is a new approach involving the development of zinc-oxygen cluster photoresists, which can not only solve the problem of the purity of zinc-oxygen clusters, but also have a clear structure; it can also solve the problem of poor thermal stability; and it is easy to implement, has good repeatability and stability ; And greatly reduce the cost.

One of the applications is to use the compound represented by the above structural formula as I or II as the only component directly as a photoresist.

The second application is to use the zinc oxide cluster compound as shown in I or II as a photoresist composition, in the composition:

The zinc oxide cluster compound represented by structural formula I or II accounts for 1-15 parts by weight, more preferably 2-4 parts by weight;

The organic solvent accounts for 85-99 parts by weight, more preferably 96-98 parts by weight;

The leveling agent accounts for 0-0.05 parts by weight, more preferably 0.02 parts by weight;

The dispersant accounts for 0-0.05 parts by weight, more preferably 0.02 parts by weight;

The tackifier accounts for 0-0.05 parts by weight, more preferably 0.01 parts by weight;

0-0.1 parts by weight of other additives, more preferably 0.05 parts by weight;

Preferably, the organic solvent includes but is not limited to one of esters, alcohols, ethers, cyclic ethers, benzene, carboxylic acids, alkanes, etc.; more preferably tetrahydrofuran, 1,4-dioxane Cyclo, benzene, toluene, p-xylene, o-xylene, m-xylene, mesitylene, chlorobenzene, fluorobenzene, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether, propylene glycol monoacetate, ethylene glycol methyl ether acetate , ethyl acetate, butyl acetate, chloroform and dichloromethane, methanol, ethanol, 1,2 dichloroethane or a mixture of one or more. The type and proportion of the organic solvent affect the coating performance of the photoresist composition, so adjusting the proportion and type of the organic solvent can improve its solubility to the matrix molecules. At the same time, the polarity of the organic solvent itself also affects the effect of the coating film.

Preferably, the leveling agent may include but not limited to acrylic compounds, fluorocarbon compounds and the like. The function of the leveling agent is to adjust the viscosity and fluidity of the photoresist system, and increase the film-forming uniformity of the photoresist.

Preferably, the dispersant may be lignosulfonate, such as sodium lignosulfonate, calcium lignosulfonate and ammonium lignosulfonate.

Preferably, the thickener may include but not limited to hexamethyldisilazane, hydroxymethylcellulose, polyacrylamide, etc., and a small amount of thickener may be evenly dispersed on the matrix material by spraying , by changing the hydrophilicity and hydrophobicity, the force between the photoresist and the matrix material is increased.

Preferably, the other additives are, for example, photoinitiators, free radical quenchers and the like.

The application of the third aspect of the present invention also includes: using the zinc oxycluster compound of the above formula I or II structure to prepare a photoresist coating, which includes using the zinc oxycluster compound or the photoresist composition of the above formula I or II structure It is prepared by applying it on the substrate to form a film; the photoresist coating is a smooth and dense uniform film, that is, a zinc oxide cluster film.

Preferably, the substrate may be selected from a silicon wafer or a quartz wafer, and may also include a silicon wafer or a quartz wafer on which sensors, circuits, transistors, etc. are formed. Film forming methods such as spray coating, vapor deposition, deposition, etc. to obtain the photoresist coating, etc., and the application method is a spin coating method.

The invention also discloses a method for optimizing the roughness of the zinc-oxygen cluster thin film. The method includes the following steps: adjusting the light intensity by adjusting the parameters of solid content, gelling solvent, glue leveling time, glue leveling speed, baking temperature and time parameters. The film-forming properties of the resist thin film; specifically, the preparation of photoresist thin films with different roughness by spin-coating process. The data is obtained from the probe-type scanning measurement of the atomic force microscope (abbreviated as AFM in the text) (10μm×10μm wide-area surface scanning). The roughness behavior of the film can be evaluated by Ra and Rq. The smaller the roughness, the smaller the fluctuation of the film and the smoother it is , Better quality film roughness Ra and Rq are usually controlled below 0.3nm.

R _a — within the scope of the sampling area, the arithmetic mean value (mean value) of the absolute value of the height deviation measured relative to the central plane, nm;

R _q —— within the scope of the sampling area, the root mean square value of the contour deviation from the mean line, which is the root mean square parameter (variance) corresponding to Ra, nm;

l——sampling length, nm;

Z _j ——the sampling height when calculating Ra, nm;

Z _i ——the sampling height when calculating Rq, nm;

The application of the fourth aspect of the present invention also includes: application of the photoresist coating in film science or photolithography. Because the zinc oxycluster compound having the structure of formula I or II described in the present invention has a very high thermal decomposition temperature, it can be used in photolithographic processing.

Preferably, the photoresist coating can be used for 248nm lithography, 193nm lithography, extreme ultraviolet (EUV) lithography, extreme extreme ultraviolet (BEUV) lithography, nanoimprint lithography or electron beam lithography, etc. Among photolithography techniques, electron beam lithography or extreme ultraviolet lithography is preferably used.

An electron beam lithography method, which comprises, the thin film prepared by the zinc oxide cluster photoresist with the formula I or II structure or its composition is subjected to uniform glue, soft baking, exposure, post-baking, development, hardening Baking; uniform glue is preferably: speed 500rpm-5000rpm, time 10s-300s, for example, spin coating at 2000rpm for 90s. The soft-baking temperature is preferably 60° C. to 160° C. for 10 s to 300 s, for example, 100° C. for 180 s. The exposure dose is preferably 20 μC/cm ² to 800 μC/cm ² at 25 kV. The post-baking temperature is preferably 40° C. to 150° C. for 10 s to 300 s, for example, 90° C. for 60 s. The developing time is preferably 10s to 300s.

The developer is compatible with the photoresists described above and is used to dissolve unexposed negative-tone photoresists. In some embodiments, the developer is selected from toluene, o-xylene, m-xylene, p-xylene, mesitylene, ethyl acetate, butyl acetate, 4-methyl 2-pentanol, 4-methyl 2-Pentanone, Methyl Ethyl Ketone, Propylene Glycol Monoformaldehyde Acetate, Propylene Glycol Acetaldehyde, Propylene Glycol Monoacetate, Ethylene Glycol Formaldehyde Acetate, 2-Butanone, 2-Heptanone, Ethanol, n-Propanol , isopropanol, n-butanol, isobutanol, ultrapure water, n-hexane and cyclohexane, and the developing temperature is room temperature, for example, 20°C to 30°C.

Beneficial effect

The selected raw materials are cheap and easy to obtain, the referenced synthesis method is simple, and the prepared product is pure.

The designed photoresist molecule is non-chemically amplified, so no photoacid generator is needed, and no acid-sensitive group is needed on the ligand unit. It can be in the form of a non-composition and is an integrated photoresist, which is convenient to implement and saves cost.

The zinc-oxygen cluster compound of the present invention adopts multi-metal sites as the core structure, has better chemical stability and higher melting point similar to MOF-5, and can meet the requirements of different advanced photolithography technologies.

The zinc-oxygen clusters described in the present invention belong to the molecular level, which has the advantage of clear structure, and is especially suitable for component analysis before and after exposure to study the exposure mechanism. X-ray photoelectron spectroscopy (XPS) research shows that the binding mode of the ligand and the metal is a coordination bond, and the molecule will break the chemical bond after exposure to generate insoluble fragmented metal oxides.

The zinc-oxygen cluster compound of the present invention is a spatially symmetrical compound, and the cost of the raw materials used is 30 times lower than the cost of the zinc-oxygen cluster photoresist mentioned in the background technology, which is economical and environmentally friendly; the purity of the zinc-oxygen cluster used is increased to 100% , can be dissolved in organic solvents commonly used in photoresist, compared with traditional zinc oxide clusters, the solubility is more than doubled.

The photoresist composition of the present invention can prepare a uniform film, and the roughness of the film can be reduced to below 0.3nm, reaching the forefront of the industry. Compared with traditional metal cluster molecules, the thermal decomposition temperature is increased by 3 times, which is beneficial to have stronger temperature regulation during pre-baking, post-baking, and hard-baking in the process. Zinc oxide as the main component in the film-making process The cluster compound does not precipitate when heated at high temperature, and the film structure does not change during high temperature baking. The traditional zinc-oxygen cluster compound deteriorates in 60 days, but the structure of the zinc-oxygen cluster compound of the present invention remains unchanged for 270 days under ordinary conditions, and the film prepared by the photoresist composition of the present invention has good solubility, film-forming property, adhesion Adhesion, thermal stability, and easy storage, stable structure, can meet the requirements of different types of photolithography technology.

Description of drawings

Figure 1A is the simulated theoretical value of the target compound TBA; Figure 1B is the experimental value of the target compound TBA

Fig. 2A, Fig. 2B, Fig. 2C, Fig. 2D are the mass spectrometric analysis of the product obtained when the work in the background technology is repeated experiment

Figure 3A is the optimization calculation of the spatial structure of the target compound TBA, and Figure 3B is the X-ray single crystal structure analysis of the target compound TBA

Figure 4 is the ¹ H NMR spectrum of TBA zinc oxide clusters

Figure 5 is the ¹³ C NMR spectrum of TBA zinc oxide clusters

Figure 6 is the ¹⁹ F NMR spectrum of TBA zinc oxide clusters

Figure 7 shows the optimization calculation of the spatial structure of the target compound BA

Figure 8 is the ¹ HNMR spectrum of BA zinc oxygen clusters

Figure 9 is the ¹³ C NMR spectrum of BA zinc oxide clusters

Figure 10A is a high-roughness film of TBA photoresist under AFM in Comparative Example 2; Figure 10C is a three-dimensional image

Figure 10B is a dense low-roughness film of TBA photoresist under AFM in Example 3; Figure 10D is a three-dimensional image

Figure 11A is a high-roughness film of TBA photoresist under AFM in Comparative Example 3; Figure 11B is a three-dimensional image

Figure 12A is a thermogravimetric image of work cited in the background art;

Fig. 12B is the thermogravimetric image of the zinc oxide cluster prepared by the present invention

Fig. 13A is the atomic force microscope (AFM) picture of the mechanical scratch measurement film thickness of embodiment three negative photoresist; Fig. 13C is three-dimensional image

Figure 13B is the line distribution of the film thickness derived by the software;

14A is the dose distribution of the square pattern obtained by electron beam exposure of the negative photoresist in Example 3;

14B is a scanning electron microscope (SEM) image of a square pattern obtained by electron beam exposure of the negative photoresist in Example 3;

14C is an SEM image of the film thickness of the square pattern obtained by electron beam exposure of the negative photoresist in Example 3 as a function of dose;

Figure 14D is a scanning electron microscope (SEM) image of the square pattern obtained by electron beam exposure of the negative photoresist in Example 3 under an unsuitable developer

15A is an atomic force microscope (AFM) image of a square pattern obtained by electron beam exposure of the negative photoresist in Example 3;

Figure 15B is a three-dimensional atomic force microscope (AFM) image of the square pattern obtained by electron beam exposure of the negative photoresist in Example 3

16A is a scanning electron microscope (SEM) image of the square and stripe patterns obtained by electron beam exposure of the negative photoresist in Example 3;

The scanning electron microscope (SEM) picture of the 500nm stripe pattern obtained by electron beam exposure of the negative photoresist in the third embodiment of Fig. 16B;

The scanning electron microscope (SEM) picture of the 300nm stripe pattern obtained by electron beam exposure of the negative photoresist in the third embodiment of FIG. 16C;

The scanning electron microscope (SEM) picture of the 100nm stripe pattern obtained by electron beam exposure of the negative photoresist in the third embodiment of Fig. 16D

Fig. 17A is the Fourier transform infrared spectrogram of negative photoresist molecule TBA and the Fourier transform infrared spectrogram of the TBA thin film prepared by spin coating in Example 3 after high temperature baking

Fig. 17B is the Fourier transform infrared spectrogram of negative photoresist molecule TBA;

Detailed ways

The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

Embodiment one

As shown in Figure 1, compound I is easy to add and anion in the negative mode of ESI mode, expressed as [M+L] ^- , the experimental value [(CF ₃ C ₆ H ₄ COO) ₆ OZn ₄ +CF ₃ C ₆ H ₄ COO] ^- = 1600.7, theoretical value 1600.8.

Comparative example one

The mass spectrometric analysis of the product obtained when carrying out repeated experiments to the work in the background technology is as shown in Figure 2, and all the structures composed of 4 metals in the mass spectrometry test results are selected for explanation, and the mass spectrometry results show that the compound is actually a mixture, shown as [M+L] ^- , experimental value:

[(C ₃ H ₅ COO) ₆ (O)Zn ₄ +CF ₃ COO] ^- = 901.03, theoretical value 901.03

[(C ₃ H ₅ COO) ₅ (CF ₃ COO)(O)Zn ₄ +CF ₃ COO] ^- = 928.99, theoretical value 928.96

[(C ₃ H ₅ COO) ₄ (CF ₃ COO) ₂ (O)Zn ₄ +CF ₃ COO] ^- = 956.97, theoretical value 956.90

[(C ₃ H ₅ COO) ₃ (CF ₃ COO) ₃ (O)Zn ₄ +CF ₃ COO] ^- = 984.90, theoretical value 984.83.

Embodiment two

The zinc-oxygen cluster structure I prepared, the simulation space optimization calculation is shown in Figure 3A, in the lowest and most stable state of energy, the chemical environment of the six Rs is exactly the same, and it is a spatially symmetrical octahedral structure, and the X-ray single crystal structure analysis is shown in Figure 3A 3B, consistent with FIG. 3A, the distance between two symmetrical fluorine atoms measured by Diamond software is about 1.97 nm.

Embodiment two

Solubility test: The prepared pure zinc oxide clusters were used for comparative solubility experiments. Among conventional solvents, the former is soluble in most commonly used organic solvents in laboratories, such as methylene chloride, methanol, ethanol, acetone, ethyl acetate, etc., and the solubility of the former is significantly better than that of the latter. Both are insoluble in water, but are better soluble in benzene solvents, such as toluene, xylene, chlorobenzene, etc. In all the examples and comparative examples, after baking process screening, it is preferable to bake at 110° C. for 60 s to obtain a relatively flat and uniform film, and this condition is used in the following examples and comparative examples.

Embodiment three

A kind of negative photoresist formula: the pure zinc oxide cluster I (being abbreviated as TBA) prepared according to the reference is dissolved in chlorobenzene, the solution that makes mass concentration is 40mg/ml, uses the aperture 0.4 μm Filter through a microporous filter to obtain a spin-coating solution, which is spin-coated on a silicon substrate to form a film, and baked at 110° C. for 60 s. The basic characterization of the prepared zinc oxide cluster TBA:

Figure 4: ¹ H NMR (400MHz, Chloroform-d) δ8.35 (d, J=8.1Hz, 12H), 7.73 (d, J=8.2Hz, 12H).

Figure 5: ¹³ C NMR (126MHz, CDCl ₃ ) δ174.98, 135.64, 134.73(q, J=32.5Hz)., 131.24, 125.30, 123.79(q, J=272.1Hz).

Figure 6: ¹⁹ F NMR (376MHz, CDCl ₃ ) δ-63.06.

Elemental analysis: C: Anal.40.82.Measure41.98, H: Anal.1.71.Measure1.68, Zn: Anal.18.52.Measure15.90.

Comparative example two

In all failed experimental examples, by controlling the remaining variables constant, select a representative comparative example: a negative photoresist formula: TBA prepared according to references is dissolved in L (-)-ethyl lactate, A solution with a mass concentration of 40 mg/ml was prepared, filtered through a microporous filter with a pore size of 0.4 μm to obtain a spin-coating solution, which was spin-coated on a silicon substrate to form a film, and baked at 110° C. for 60 s.

Comparative example three

The prepared zinc-oxygen cluster structure II, the simulation space optimization calculation is shown in Figure 7 (abbreviated as BA). The comparison molecule BA is selected as a comparison example. Since the solubility of BA is inferior to TBA, in order to obtain a film with lower roughness, the mass concentration is set to 40mg/ml, a negative photoresist formula: dissolve zinc oxide clusters (abbreviated as BA) prepared according to references in chlorobenzene to obtain a solution with a mass concentration of 20mg/ml, and use a pore size of 0.4 Filter through a microporous filter of μm to obtain a spin-coating solution, which is spin-coated on a silicon substrate to form a film, and baked at 110°C for 60s. The basic characterization of the prepared zinc oxide cluster BA:

Figure 8: ¹ H NMR (400MHz, Chloroform-d) δ8.24–8.19 (m, 12H), 7.52 (t, J = 7.4 Hz, 6H), 7.42 (t, J = 7.6 Hz, 12H).

Figure 9: ¹³ C NMR (101MHz, DMSO) δ171.84, 134.75, 130.99, 129.57, 127.94.

Elemental analysis: C: Anal.50.23.Measure50.52, H: Anal.3.01.Measure2.82, Zn: Anal.26.04.Measure22.16.

Comparative example four

For all the above examples and comparative examples, in order to improve the uniformity of the film, the formula photoresist after adding the vinyltrimethoxysilane of 0.02 parts by weight of the additive, the roughness measured by AFM does not improve the film quality, Some additives, such as photoacid generator N-hydroxynaphthoimide trifluoromethanesulfonic acid, have poor solubility, which affects the quality of the membrane to a certain extent, and should be added for necessary purposes. In all subsequent experiments, no additives were added and the silicon wafers were not treated in any way.

Embodiment four

In order to measure the quality of the spin-coated film, the film morphology was collected by AFM probe scanning, and the collection range was 10 μm×10 μm. Taking comparative example 2 as a representative failure example (comparative group data), the high-roughness film of TBA photoresist under AFM is shown in Figure 10A, and Figure 10C is a three-dimensional image. Roughness _Ra = 10.06 nm, R _q = 17.06 nm. Through the summary of a large number of failure cases that have not been written into the specific embodiments, the quality of the film is finally optimized by improving the spin coating process, adjusting the rotation speed, improving the baking temperature, and changing the solvent. The roughness is reduced from nanometer level to picometer level. In the third embodiment above, a low-roughness film under AFM is obtained, which is very dense as shown in Figures 10B and 10D, where _Ra = 191.7pm, _Rq = 245.8pm. In addition, although the BA structure also has a certain solubility, the roughness of the BA photoresist does not reach the effect of the TBA photoresist. The images of the film in Comparative Example 3 under AFM are shown in Figures 11A and 11B, where The roughness R _a =2.386nm and _Rq =2.993nm are higher than the roughness of the TBA photoresist shown in Example 3 ( FIG. 10B ). Embodiment 3 meets the film thickness requirements of future advanced photolithography technology, and has very high-quality film properties.

Embodiment five

Figure 12A is a thermogravimetric image that cites the work in the background technology. Since the product is a mixture, and some unreacted ligands are suspended on the main structure, ligand loss occurs at about 100°C; Figure 12B is a reference for the present invention The thermogravimetric images of zinc-oxygen clusters prepared in the literature have not been reported on the thermogravimetric effect. Among them, the remaining weight loss of TBA and BA is 23.27% and 30.35%, indicating that zinc oxide or zinc hydroxide is formed after vaporization. For the first time, it was found that this pure zinc oxide cluster has a higher thermal decomposition temperature, and the thermogravimetric images are similar, and the thermal decomposition temperature is increased by 3 times, which is beneficial to have a stronger performance in the pre-baking, post-baking, and hard-baking processes in the process. Excellent temperature regulation, the zinc oxide cluster compound as the main component does not precipitate when heated at high temperature during the film forming process.

Embodiment six

Figure 7 is a study of film thickness. Figure 13A uses a utility knife to scratch the silicon wafer with spin-coated photoresist on the low-roughness film prepared in Example 3 (Figure 13C is a three-dimensional image), and uses AFM probe scanning to measure the depth of the scratch for Characterize film thickness. Fig. 13B is the measurement of the film thickness, and the measurement result is 56.0nm.

Embodiment seven

FIG. 14 is the exposure result of the photoresist prepared in Example 3 in the exposure experiment on the electron beam exposure machine, which is used for the sensitivity measurement experiment. Scanning electron microscope (SEM) images of the photoresist exposed at different doses in FIG. 14A are shown in FIGS. 14B and 14D. The development conditions include developer type, proportion, development time, baking time and temperature, etc. Under unsuitable development conditions, such as MIBK:IPA=1:3, the comparison graph obtained by developing for 30s is shown in Figure 14D, and the results show that , did not get a well-developed square pattern and could not be applied to sensitivity measurement experiments. Finally, the development conditions were determined as developing with n-hexane for 30 seconds, fixing with ultrapure water for 2 seconds, and drying at 150° C. for 30 seconds after drying with nitrogen. Figure 14B Scanning Electron Microscope (SEM) image is the exposure result of Zn-TBA photoresist under the optimal development condition with electron beam exposure machine for sensitivity experiment. 14C, the results show that the optimal dosage of the prepared photoresist film is 550 μC/cm ² .

Embodiment eight

FIG. 15 shows the photoresist of Example 3 processed by photolithography to obtain a partial image with a photolithography pattern of 10 μm×10 μm, and FIG. 15B is the stereoscopic image of FIG. 15A . The thickness of the film can be characterized by the negative film after exposure and development, and the AFM probe scanning result is about 54 nm, which is basically consistent with the value measured by scratch damage in Example 6.

Embodiment nine

Figure 16 shows the exposure results of the exposure experiment on the electron beam exposure machine for the film prepared in Example 3 under the optimal dose of Example 16. The developing conditions are: n-hexane solution for 30 s, ultrapure water for 2 s for fixation, and nitrogen blowing for 2 s , bake at 90°C for 30s. In Fig. 16A, from left to right, there are 10 μm squares, 5 100nm lines, 5 300nm lines, and 5 500nm lines, and the duty ratio L:S=1:2. Figures 16B-16D show that each line is well developed, and a photolithographic pattern with a stripe width of 100nm and a period of 300nm can be obtained at most, indicating that the prepared photoresist has high-resolution imaging capability. In view of the excellent physical and chemical properties of the zinc oxide cluster used in the present invention, its photolithography effect is expected to be further explored and verified.

Comparative example seven

Repeated exposure experiments on the zinc-oxygen clusters in the background technology showed that the dose required for each exposure was different, which indicated that the batch stability of the zinc-oxygen clusters synthesized each time was poor, resulting in the same number of reactive groups contained in the product. Different numbers of clusters lead to different light doses required for each batch of synthetic products, so the ratio of the mixture generated in each reaction is random. However, after the zinc oxide clusters of the present invention are accurately weighed and formulated into gels, the exposure dose used each time has good repeatability.

Embodiment ten

Figure 17A shows that there is no change in the structure of the film after baking at a high temperature of 150°C for 5 minutes. Figure 17B is the Fourier transform infrared spectrum of the pure TBA sample placed in a sealed glass bottle under natural conditions for six months and nine months, Zn-O-Zn stretching vibration near 516s, and substituted benzene at 711m~869m The CH out-of-plane bending vibration of the ring, the CH in-plane bending vibration of the benzene ring and the stretching vibration of CO and CF bonds at 1020m~1168m, the strong stretching vibration of CF at 1326s and 1430s, and the C=C of the benzene ring skeleton at 1517m~1619s Stretching vibration. The gray area marked around 3000cm ^-1 has no carboxyl group and a typical -OH broad peak, indicating that there is no decarboxylation phenomenon, while the peak type at 3500cm ^-1 is a typical water peak. It can be seen that the water peak signal gradually increases with the increase of storage time. Enhanced, while the wave number of the remaining characteristic peaks has no obvious shift, and the signal has no obvious change, it can be explained that the photoresist molecule has good storage stability. The traditional zinc-oxygen cluster compound deteriorates in 60 days. The zinc-oxygen cluster compound used in the present invention is in the Under normal conditions, there is no change in the structure after 270 days of storage, which is 3 times higher than that of traditional zinc oxide clusters that are unstable in storage.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (11)

1. The application of a class of zinc-oxygen cluster compounds in the field of photoresists, characterized in that: the general structural formula of the zinc-oxygen cluster compounds is as shown in A:

Wherein: R is selected from one of the following substituents:

2. The application according to claim 1, characterized in that: the application includes using the zinc oxide cluster compound I or II shown in A as the only component directly used as a photoresist

3. The use according to claim 1, characterized in that said use comprises as a photoresist composition. 4. application according to claim 1, is characterized in that: described application comprises the photoresist composition that utilizes above-mentioned structural formula such as the zinc oxide cluster compound preparation of I or II, and described composition comprises following component by Composition in parts by weight: Zinc oxide cluster compounds with structural formulas such as I or II account for 1 to 15 parts by weight; Organic solvent accounts for 85～99 parts by weight; The leveling agent accounts for 0-0.05 parts by weight; The dispersant accounts for 0 to 0.05 parts by weight; The tackifier accounts for 0 to 0.05 parts by weight; 0-0.1 parts by weight of other additives; The organic solvent includes one of esters, alcohols, ethers, cyclic ethers, benzenes, carboxylic acids, and alkanes; The other additives are selected from photoinitiators and/or free radical quenchers. 5. The application according to claim 4, characterized in that: said organic solvent comprises tetrahydrofuran, 1,4-dioxane, benzene, toluene, p-xylene, o-xylene, m-xylene, mesitylene , chlorobenzene, fluorobenzene, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether, propylene glycol monoacetate, ethylene glycol methyl ether acetate, ethyl acetate, butyl acetate, chloroform and dichloromethane, methanol, ethanol, 1, 2 One or more mixtures of dichloroethanes. 6. application according to claim 1, is characterized in that: described application comprises the photoresist coating that utilizes zinc oxide cluster compound or photoresist composition of above-mentioned structural formula such as I or II to be applied on the substrate to form a film . 7. The application according to claim 6, characterized in that: said application includes a method for optimizing the zinc oxide cluster photoresist coating, comprising the steps of: adjusting the solid content, compounding solvent, uniform glue time, Coating rotation speed, baking temperature and time parameters are used to adjust the film-forming characteristics to obtain zinc-oxygen cluster films. 8. The application according to claim 7, characterized in that: the application is that the data of the zinc-oxygen cluster thin film is obtained by the probe type scanning measurement of the atomic force microscope, and the roughness behavior of the thin film is evaluated by Ra and Rq, and the prepared The film _Ra and _Rq of the film are both below 0.3nm, and the roughness Ra and Rq of the better quality film are controlled below 0.3nm;

R _a — within the scope of the sampling area, the arithmetic mean value of the absolute value of the height deviation measured relative to the central plane, nm; R _q —— within the scope of the sampling area, the root mean square value of the contour deviation from the mean line, which is the root mean square parameter corresponding to Ra, nm; l——sampling length, nm; Z _j ——sampling height when calculating _Ra , nm; Z _i ——the sampling height when calculating R _q , nm. 9. The application according to claim 6, characterized in that: the application includes the application of the photoresist coating in film science or photolithography. 10. The application according to claim 6, characterized in that: the application includes using the photoresist coating for 248nm lithography, 193nm lithography, extreme ultraviolet lithography, extreme extreme ultraviolet lithography, nanoimprint Photolithography or electron beam lithography. 11. The application according to claim 6, characterized in that: the application comprises an electron beam lithography method, characterized in that: the photoresist coating according to claim 4 is subjected to leveling, soft baking, and exposure , post-baking, developing, hard-baking; uniform glue: speed 500rpm-5000rpm, time 10s-300s, soft-baking temperature 60℃-160℃, time 10s-300s; developing time 10s-300s.

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