A composite coating for a semiconductor device and a method of making the same

Abstract

This application belongs to the field of semiconductor technology and discloses a composite coating for semiconductor devices and its preparation method. The preparation method includes the following steps: adding an organic resin and a carbon raiser to an alcohol solvent and mixing them evenly to obtain a resin solution; adding a tantalum source and a phase-forming promoter to the alcohol solvent and stirring to obtain a tantalum solution; coating the resin solution and tantalum solution onto a substrate surface, heating to cure, carbonizing, and cooling to obtain a composite coating containing glassy carbon and tantalum carbide. The composite coating is a single-layer structure or a double-layer structure. The single-layer structure is a composite single-layer coating containing glassy carbon and tantalum carbide; the double-layer structure consists of a glassy carbon layer and a glassy carbon and tantalum carbide composite layer from bottom to top on one side of the substrate surface. The composite coating obtained by the above method can effectively improve its density, thereby improving its corrosion resistance in a plasma environment.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a composite coating for semiconductor devices and a method for preparing the same. Background Technology

[0002] Glassy carbon coating is produced by subjecting organic precursors (such as phenolic resins) to high-temperature pyrolysis under inert gas protection. This process causes complex decomposition and condensation reactions of the organic matter, ultimately transforming it into a dense, high-purity carbon layer with a unique glassy structure. Thanks to its unique microstructure, glassy carbon coating combines the hardness of ceramics with the smoothness of glass, exhibiting excellent thermal stability, high electrical conductivity, and superior chemical inertness. In particular, it demonstrates strong resistance to corrosion from most acid, alkali, and salt solutions. These outstanding comprehensive properties make it a promising candidate for applications in many high-end technology fields, especially meeting the stringent requirements of semiconductor manufacturing processes. In the semiconductor industry, this coating has been widely used in front-end substrate treatment and doping processes, mid-end thin film deposition and photolithography processes, and back-end packaging and testing stages, effectively ensuring wafer cleanliness and device performance stability.

[0003] However, in practical applications, especially in plasma environments composed of a large number of electrons, ions, neutral free radicals, and excited-state atoms, the impact on the coating mainly includes two aspects: First, physical sputtering, where high-energy ions accelerated by an electric field violently bombard the coating surface, directly breaking C-C bonds through momentum transfer, causing carbon atoms or clusters to be sputtered off, resulting in surface physical damage and structural loosening; second, chemical etching, where highly reactive free radicals generated in the plasma react with carbon atoms on the coating surface through chemical adsorption, generating volatile products that are then extracted, leading to continuous material loss. Under the synergistic effect of these two factors, the dense structure of the coating surface is gradually destroyed, micropores and defects increase, and consequently, its inherent corrosion resistance undergoes irreversible degradation. Summary of the Invention

[0004] The technical problem to be solved by this invention is to propose a composite coating for semiconductor devices and a method for preparing the same, which aims to solve the problem that the corrosion resistance of glass carbon coatings decreases due to the decrease in density in a plasma environment.

[0005] To address the aforementioned technical problems, this invention proposes a method for preparing a composite coating for semiconductor devices, comprising the following preparation steps:

[0006] S1. Add organic resin and carbon raiser to alcohol solvent and mix evenly to obtain resin solution. The carbon raiser is used to increase the residual carbon content of organic resin after carbonization.

[0007] S2. Add the tantalum source and the phase-forming promoter to the alcohol solvent, stir and mix to obtain a tantalum solution. The phase-forming promoter is a non-metallic phase-forming promoter used to reduce the temperature at which the tantalum source forms tantalum carbide.

[0008] S3. Coat the substrate surface with resin solution and tantalum solution, heat to cure, carbonize and cool to obtain a composite coating containing glassy carbon and tantalum carbide, wherein the composite coating is a single-layer structure or a double-layer structure.

[0009] The single-layer structure is a composite single-layer coating containing glassy carbon and tantalum carbide.

[0010] The dual-layer structure consists of a glassy carbon layer and a glassy carbon and tantalum carbide composite layer from bottom to top on one side of the substrate surface.

[0011] In some embodiments, the alcohol solvent is ethanol and / or methanol, the mass ratio of organic resin: carbon raiser: alcohol solvent in step S1 is 1:(0.1~0.3):(0.5~1), the mass ratio of tantalum source: phase formation promoter: alcohol solvent in step S2 is (0.3~0.7):(0.05~0.2):1, and the carbonization temperature in step S3 is 1600~1800℃.

[0012] In some embodiments, the organic resin in step S1 is phenolic resin and / or epoxy resin, the carbon raiser includes at least one of nano carbon powder, carbon black, and graphene, the tantalum source in step S2 is tantalum powder and / or tantalum pentoxide, and the particle size of the tantalum source is 50~500nm, and the phase formation promoter includes at least one of boric acid, ammonium phosphate, and urea.

[0013] In some embodiments, when the composite coating is a single-layer structure, step S3 includes:

[0014] S3.1 Add an amino modifier to the resin solution, heat to 60-90℃, reflux and condense for 2-4 hours to obtain an amino-modified resin solution, wherein the mass of the amino modifier is 3-8 wt% of the mass of the organic resin;

[0015] S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 min to obtain a complexed modified tantalum solution, wherein the mass of the diketone complexing agent is 10-20 wt% of the mass of the tantalum source;

[0016] S3.3 Mix the ammonia-modified resin solution and the complex-modified tantalum solution, stir at room temperature for 30-60 minutes to obtain a composite solution, then coat the composite solution onto the substrate, cure at 100-120℃ for 1-2 hours, then place it in an inert atmosphere, first heat to 600-900℃ for 1-2 hours, then heat to 1600-1800℃ for 1-3 hours, and cool to room temperature to obtain a composite single-layer coating containing glassy carbon and tantalum carbide.

[0017] In some embodiments, when the composite coating is a two-layer structure, step S3 includes:

[0018] S3.1 Divide the resin solution into two equal portions, and then directly coat the first portion of the resin solution onto the substrate surface. Pre-dry at 80~100℃ for 15~30 minutes to obtain a resin coating.

[0019] S3.2. Mix the second resin solution with the tantalum solution to obtain a composite solution. Then, coat the composite solution onto the resin coating and cure it at 100~120℃ for 1~2 hours. Then, heat it to 600~900℃ for 1~2 hours and finally heat it to 1600~1800℃ for 1~3 hours. Cool it to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

[0020] In some embodiments, when the composite coating is a two-layer structure, step S3 further includes:

[0021] S3.1 Divide the resin solution into two equal portions. Add an amino modifier to the first portion of the resin solution, heat to 60-90℃, reflux and condense for 2-4 hours to obtain an amino-modified resin solution. Then, coat the amino-modified resin solution onto the substrate surface and pre-dry at 80-100℃ for 15-30 minutes to obtain a resin coating. The mass of the amino modifier is 3-8 wt% of the mass of the organic resin contained in the first portion of the resin solution.

[0022] S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 minutes to obtain a complexed modified tantalum solution. Then mix it with the second resin solution and an aldehyde-containing interface reinforcing agent to obtain a composite solution. The mass of the diketone complexing agent is 10-20 wt% of the tantalum source mass, and the mass of the aldehyde-containing interface reinforcing agent is 3-8 wt% of the organic resin contained in the second resin solution.

[0023] S3.3. Apply the composite solution to the resin coating, cure at 100~120℃ for 1~2h, then heat to 600~900℃ for 1~2h, and finally heat to 1600~1800℃ for 1~3h. Cool to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

[0024] In some embodiments, the amino modifier in step S3.1 includes at least one of diethylenetriamine, polyethyleneimine, and triethylenetetramine, and the diketone complexing agent in step S3.2 includes at least one of acetylacetone, benzoylacetone, and furanoylacetone.

[0025] In some embodiments, the aldehyde-containing interface enhancer in step S3.2 includes at least one of furfural, 5-hydroxymethylfurfural, and terephthalaldehyde.

[0026] In addition, a composite coating for semiconductor devices is also provided, wherein the semiconductor substrate composite coating is prepared by the above-described method for preparing a composite coating for semiconductor devices.

[0027] The beneficial effects of this invention are:

[0028] First, a carbon raiser is introduced into the resin solution. During high-temperature carbonization, the carbon raiser, as an exogenous solid carbon particle, fills the micropores between the glass carbon skeleton and tantalum carbide grains, effectively compensating for the volume shrinkage caused by resin pyrolysis, directly increasing the physical packing density of the coating, blocking the penetration channels of active free radicals in the plasma, and improving the density and impermeability of the coating from a structural level. Secondly, by adding a non-metallic phase-forming promoter to the tantalum solution, the reactants change from a liquid to a solid state upon heating. The promoter decomposes to produce a low-melting-point intermediate phase and gaseous products, which wet the reactant interface, transforming the solid-solid reaction into a localized solid-liquid or solid-gas reaction. This increases the atomic migration rate, lowers the tantalum carbide formation temperature, and avoids the coarse grains and thermal stress cracking caused by traditional high-temperature processes. Simultaneously, the promoter decomposition products alter the precipitation environment of tantalum carbide, causing a large number of crystal nuclei to precipitate synchronously throughout the reaction interface region. The number of crystal nuclei per unit volume significantly increases, achieving grain refinement and making the grain boundary path tortuous, effectively extending the penetration channels of the corrosive medium. Through the synergistic effect of the physical filling and densification of the carbon-reinforcing agent and the intrinsic corrosion resistance and grain refinement of tantalum carbide, the composite coating exhibits a dense structure and fine grain microstructure. The dense structure blocks corrosion channels, and the tantalum carbide phase directly resists chemical attack. Together, these two factors enable the coating to effectively resist corrosion and sputtering in a plasma etching environment, significantly delaying coating failure and greatly extending the service life of the semiconductor substrate. Attached Figure Description

[0029] Figure 1 This is a schematic flowchart of a method for preparing a semiconductor substrate composite coating in one embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the composite coating structure obtained in Embodiment 1 of the present invention, wherein 1 is a semiconductor substrate, 3 is a glassy carbon and tantalum carbide combined coating, and 4 is tantalum carbide in the glassy carbon and tantalum carbide combined coating.

[0031] Figure 3 This is a schematic diagram of the composite coating structure obtained in Embodiment 3 of the present invention, wherein 1 is a semiconductor substrate, 2 is a glassy carbon coating, 3 is a glassy carbon and tantalum carbide combined coating, and 4 is tantalum carbide in the glassy carbon and tantalum carbide combined coating. Detailed Implementation

[0032] In the description of this application, it should be noted that, unless specific conditions are specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0033] Please refer to Figure 1 This application provides a method for preparing a composite coating for semiconductor devices, the method comprising the following preparation steps:

[0034] S1. Add organic resin and carbon raiser to alcohol solvent and mix evenly to obtain resin solution. The carbon raiser is used to increase the residual carbon content of organic resin after carbonization.

[0035] By introducing a carbon raiser into the resin solution, during high-temperature carbonization, the carbon raiser acts as an exogenous solid carbon particle to fill the micropores between the glass carbon skeleton and tantalum carbide grains, effectively compensating for the volume shrinkage caused by resin pyrolysis, directly increasing the physical packing density of the coating, blocking the penetration channels of active free radicals in the plasma, and improving the compactness and impermeability of the coating from a structural level.

[0036] In step S1, the alcohol solvent is ethanol and / or methanol, the organic resin is phenolic resin and / or epoxy resin, and the carbon raiser includes at least one of nano carbon powder, carbon black, and graphene. The mass ratio of organic resin: carbon raiser: alcohol solvent is 1:(0.1~0.3):(0.5~1).

[0037] The organic resin is selected from at least one of phenolic resin, furan resin, or epoxy resin. All three are thermosetting resins with high carbon residue rates, which can be transformed into a dense and chemically inert glassy carbon matrix after high-temperature carbonization. The alcohol solvent is selected from ethanol and / or methanol, which utilize their excellent solubility in the resin to transform the solid resin into a solution with a suitable viscosity, while ensuring that it can completely evaporate without residue after coating and avoid introducing impurities. The carbon raiser is selected from at least one of nano-carbon powder, carbon black, or graphene. All three are high-purity carbonaceous materials with good thermal stability and excellent compatibility with the glassy carbon matrix. They can be uniformly dispersed in the resin matrix during high-temperature heat treatment, effectively compensating for carbonization shrinkage.

[0038] S2. Add the tantalum source and the phase-forming promoter to the alcohol solvent and stir to mix to obtain a tantalum solution. The phase-forming promoter is a non-metallic phase-forming promoter used to reduce the temperature at which the tantalum source forms tantalum carbide.

[0039] Adding a non-metallic phase-forming promoter to a tantalum solution causes the reactants to change from a liquid to a solid state upon heating. The promoter decomposes to produce a low-melting-point intermediate phase and gaseous products, which wet the reactant interface, transforming the solid-solid reaction into a local solid-liquid or solid-gas reaction. This increases the atomic migration rate, lowers the tantalum carbide formation temperature, and avoids the grain coarsening and thermal stress cracking caused by traditional high-temperature processes. Simultaneously, the promoter decomposition products alter the precipitation environment of tantalum carbide, causing a large number of crystal nuclei to precipitate synchronously throughout the reaction interface region. The number of crystal nuclei per unit volume increases significantly, resulting in grain refinement. This also makes the grain boundary path tortuous and effectively extends the penetration channel of the corrosive medium.

[0040] Wherein, the alcohol solvent is ethanol and / or methanol, the tantalum source in step S2 is tantalum powder and / or tantalum pentoxide, and the particle size of the tantalum source is 50~500nm, the phase formation promoter includes at least one of boric acid, ammonium phosphate, and urea, and the mass ratio of tantalum source: phase formation promoter: alcohol solvent is (0.3~0.7):(0.05~0.2):1.

[0041] Furthermore, to ensure better chemical stability and corrosion resistance of the subsequent carbonized coating at high temperatures, the tantalum source used must have a purity of at least 99.99%.

[0042] Tantalum powder and tantalum pentoxide, as high-purity tantalum sources, can react with resin carbon during high-temperature carbonization to form tantalum carbide ceramic phase in situ. Their nanoscale particle size significantly increases the reactive interface, which is beneficial for reducing the carbonization temperature and promoting the uniform nucleation and dense filling of tantalum carbide grains. The high purity of over 99.99% eliminates the risk of metal impurities contaminating semiconductor devices from the source. At the same time, boric acid, ammonium phosphate, or urea are selected as phase-forming promoters. All three are non-metallic compounds without metal ions. They can effectively reduce the formation temperature of tantalum carbide and inhibit abnormal grain growth by decomposing to generate active intermediate phases or controlling the local reaction atmosphere during pyrolysis. This results in a composite coating with fine grains, dense structure, and no metal contamination, which significantly enhances its corrosion resistance in harsh high-temperature and plasma environments.

[0043] S3. Coat the substrate surface with resin solution and tantalum solution, heat to cure, carbonize, and cool to obtain a composite coating containing glassy carbon and tantalum carbide, wherein the composite coating is a single-layer structure or a double-layer structure.

[0044] When the composite coating is a single-layer structure, step S3 includes:

[0045] S3.1 Add an amino modifier to the resin solution, heat to 60~90℃ and reflux for 2~4 hours to obtain an amino modified resin solution, wherein the mass of the amino modifier is 3~8 wt% of the mass of the organic resin.

[0046] For epoxy resins, whose molecular chains contain active epoxy groups, the addition of an amino modifier allows the amino group in the modifier molecule to act as a nucleophile, launching a ring-opening addition reaction to generate an addition product containing an amino group. This directly bonds the amino group to the cross-linked network of the epoxy resin. For phenolic resins, the amino group in the amino modifier can undergo a condensation reaction with the hydroxymethyl group in the phenolic resin to form a methylene bridge or imine bond, thereby introducing amino functional groups onto the side chain of the phenolic resin. Throughout the reaction, the temperature is controlled between 60 and 90°C to ensure a moderate reaction rate while avoiding premature gelation of the resin due to excessively high temperatures. A reaction time of 2 to 4 hours ensures sufficient grafting of the modifier. The final ammonia-modified resin solution shows that a large number of active amino sites are successfully anchored on the resin molecular chain.

[0047] S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 min to obtain a complexed modified tantalum solution, wherein the mass of the diketone complexing agent is 10-20 wt% of the mass of the tantalum source.

[0048] When a diketone complexing agent is added to a tantalum solution, under stirring conditions at room temperature, the diketone complexing agent molecules, with their characteristic β-diketone structure (O=CCC=O), coordinate with tantalum ions on the surface of the tantalum source particles. This results in the diketone complexing agent molecules tightly encapsulating the surface of the tantalum source particles, forming a dense organic coordination layer. For tantalum powder, the naturally occurring oxide layer on its surface provides the tantalum ion sites required for coordination; for tantalum pentoxide, the tantalum ions directly exposed on its surface can also coordinate with the diketone complexing agent. Stirring for 30–60 min ensures that the complexing agent is fully adsorbed and completes the coordination reaction. The amount added is controlled within the range of 10–20 wt% of the tantalum source mass, which ensures the formation of a complete monolayer coating on the surface of the tantalum source particles while avoiding excessive complexing agent remaining free in the solution, which would increase the porosity of the subsequent coating. In the final complexed modified tantalum solution, the surface of the tantalum source particles is uniformly coated with an organic coordination layer of diketone complexing agent. This not only effectively prevents the aggregation of nanoparticles through steric hindrance, but more importantly, it introduces active groups on the particle surface that can form hydrogen bonds with amino groups or further coordinate with them.

[0049] S3.3 Mix the ammonia-modified resin solution and the complex-modified tantalum solution, stir at room temperature for 30-60 minutes to obtain a composite solution, then coat the composite solution onto the substrate, cure at 100-120℃ for 1-2 hours, then place it in an inert atmosphere, first heat to 600-900℃ for 1-2 hours, then heat to 1600-1800℃ for 1-3 hours, and cool to room temperature to obtain a composite single-layer coating containing glassy carbon and tantalum carbide.

[0050] When the ammonia-modified resin solution and the complexed tantalum solution are mixed, during stirring at room temperature for 30-60 minutes, hydrogen bonds are formed between the active amino groups introduced on the ammonia-modified resin molecular chain and the carbonyl oxygen groups contained in the diketone complexing agent on the surface of the complexed tantalum source particles. This intermolecular force chemically anchors the tantalum source particles to the resin molecular chain. Simultaneously, the long-chain structure of the resin effectively prevents particle aggregation through steric hindrance. Combined with the shear force of mechanical stirring, the tantalum source particles are uniformly dispersed in the resin solution. After coating the composite solution onto the substrate, during curing at 100-120℃ for 1-2 hours, the solvent evaporates while the resin undergoes a cross-linking reaction, forming a three-dimensional network structure. This anchors the uniformly dispersed tantalum source particles in situ within the resin network, preventing particle migration and re-aggregation during the drying process. Subsequently, the resin matrix is ​​heated to 600-900℃ in an inert atmosphere for 1-2 hours for carbonization. During this process, the resin matrix undergoes thermal decomposition and carbonization, and the organic molecular chains break and recombine, gradually transforming into an amorphous glassy carbon matrix. Simultaneously, the tantalum source particles are encapsulated within the carbon network. Further heating to 1600-1800℃ for 1-3 hours allows for in-situ carbothermic reduction of the tantalum source with the surrounding carbon matrix, generating a tantalum carbide (TaC) reinforcing phase. Ultimately, a dense composite monolayer coating with uniformly distributed glassy carbon and tantalum carbide is formed. Throughout this process, initial hydrogen bonding anchoring ensures uniform dispersion of the tantalum source, while the in-situ reaction at high temperature enables the in-situ formation and strong bonding of the reinforcing phase.

[0051] When the composite coating has a two-layer structure, step S3 includes:

[0052] S3.1 Divide the resin solution into two equal portions, and then directly coat the first portion of the resin solution onto the substrate surface. Pre-dry at 80~100℃ for 15~30 minutes to obtain a resin coating.

[0053] Applying the first resin solution as the base layer can form a uniform carbon-rich transition layer on the graphite substrate surface, improving the interfacial adhesion between the substrate and the coating. The pre-drying temperature of 80~100℃ is mild and moderate, which can slowly evaporate some of the solvent to avoid sagging during coating, and keep the resin in an incompletely cross-linked gel state. The pre-drying time of 15~30min is precisely controlled within the critical window before the base resin is completely cured, so that its surface and shallow areas retain abundant active functional groups and swollen network structures, providing sufficient penetration channels for the subsequent composite solution, realizing the gradient transition of interlayer components and the mutual diffusion at the molecular scale, fundamentally eliminating the obvious interface between the two layers, significantly enhancing the bonding strength and suppressing the risk of delamination and cracking during high-temperature treatment.

[0054] S3.2. Mix the second resin solution with the tantalum solution to obtain a composite solution. Then, coat the composite solution onto the resin coating and cure it at 100~120℃ for 1~2 hours. Then, heat it to 600~900℃ for 1~2 hours and finally heat it to 1600~1800℃ for 1~3 hours. Cool it to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

[0055] When coated onto a gel-like substrate, the solvent in the composite solution carries a portion of the tantalum source into the substrate network, forming an interlocking interface with continuously changing composition. Curing at 100-120℃ for 1-2 hours allows the bilayer resin to fully crosslink and fix. Medium-temperature carbonization at 600-900℃ for 1-2 hours carbonizes the resin skeleton while the tantalum source decomposes into nano-tantalum oxide and is uniformly embedded in the carbon matrix. High-temperature carbonization at 1600-1800℃ for 1-3 hours drives the carbothermic reduction reaction to proceed fully, generating a fine-grained and uniformly distributed tantalum carbide ceramic phase, and further graphitizing and densifying the glassy carbon matrix. The stepped heating process avoids coating cracking and tantalum source agglomeration caused by direct high-temperature treatment. The resulting bilayer structure achieves a natural transition of composition gradient due to the presence of the interfacial diffusion layer, maintaining the buffering performance of the pure glassy carbon substrate while leveraging the corrosion resistance of the surface tantalum carbide layer. The interlayer bonding is strong and the overall density is excellent.

[0056] In one embodiment, step S3 further includes:

[0057] S3.1 Divide the resin solution into two equal portions. Add an amino modifier to the first portion of the resin solution, heat to 60-90℃ and reflux for 2-4 hours to obtain an amino modified resin solution. Then coat the amino modified resin solution onto the substrate surface and pre-dry at 80-100℃ for 15-30 minutes to obtain a resin coating. The mass of the amino modifier is 3-8 wt% of the mass of the organic resin contained in the first portion of the resin solution.

[0058] S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 minutes to obtain a complexed modified tantalum solution. Then mix it with the second resin solution and the aldehyde-containing interface reinforcing agent to obtain a composite solution. The mass of the diketone complexing agent is 10-20 wt% of the tantalum source mass, and the mass of the aldehyde-containing interface reinforcing agent is 3-8 wt% of the organic resin contained in the second resin solution.

[0059] S3.3. Apply the composite solution to the resin coating, cure at 100~120℃ for 1~2h, then heat to 600~900℃ for 1~2h, and finally heat to 1600~1800℃ for 1~3h. Cool to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

[0060] In the above preparation steps, the amino modifier includes at least one of diethylenetriamine, polyethyleneimine, and triethylenetetramine; the diketone complexing agent includes at least one of acetylacetone, benzoylacetone, and furfuralylacetone; and the aldehyde-containing interface reinforcing agent includes at least one of furfural, 5-hydroxymethylfurfural, and terephthalaldehyde.

[0061] When a composite solution containing an aldehyde-based interfacial reinforcing agent is coated onto the underlying resin coating, during the curing process at 100-120°C, the aldehyde groups in the interfacial reinforcing agent molecules, as small molecules, have strong diffusion capabilities. They penetrate and migrate into the incompletely cross-linked areas of the underlying resin coating and undergo Schiff base condensation reactions with the residual amino groups in the underlying layer to generate C=N covalent bonds, thereby forming a chemically bonded interfacial transition layer between the two layers. At the same time, the furan ring (furfural, 5-hydroxymethylfurfural) or benzene ring (terephthalaldehyde) structures in the interfacial reinforcing agent molecules have good compatibility with the surface resin, and further enhance physical entanglement through molecular chain diffusion and interpenetration. During the subsequent carbonization process at 600-900℃, the interface reinforcing agent molecules undergo thermal decomposition and carbonization. Their furan rings undergo ring-opening recombination or benzene ring condensation to participate in the construction of the carbon six-membered ring network. Since one end of the interface reinforcing agent molecule is connected to the bottom layer through covalent bonds and the other end is fused with the carbonization product of the surface resin, a continuous and interconnected carbon skeleton is formed after carbonization, connecting the two layers of carbon materials into one at the atomic scale. In the high-temperature heat treatment stage at 1600-1800℃, the carbon structure in the interface region is further graphitized, the continuity of the carbon skeleton is enhanced, and a transition zone of carbon materials is formed. This not only eliminates the physical interface but also realizes the dual connection of chemical bonds and carbon skeleton, significantly improving the bonding strength between the two layers of solid carbon materials.

[0062] The present invention also provides a composite coating for semiconductor devices, wherein the semiconductor substrate composite coating is prepared by the above-described method for preparing a composite coating for semiconductor devices.

[0063] For example, the present invention provides the following specific embodiments to illustrate the specific preparation method:

[0064] Example 1

[0065] S1. Phenolic resin and nano-carbon powder are added to ethanol and mixed evenly to obtain a resin solution, wherein the mass ratio of phenolic resin: nano-carbon powder: ethanol is 1:0.2:0.8.

[0066] S2. Add tantalum powder with a purity of 99.99% and boric acid to ethanol, stir and mix to obtain a tantalum solution, wherein the mass ratio of tantalum powder:boric acid:ethanol is 0.5:0.1:1;

[0067] S3. Mix the resin solution and tantalum solution at a mass ratio of 1:0.5, stir at room temperature for 45 minutes to obtain a composite solution, then coat the composite solution onto the substrate, cure at 110℃ for 1.5 hours, then place in an inert atmosphere, first heat to 750℃ for 1.5 hours, then heat to 1700℃ for 2 hours, and cool to room temperature to obtain the desired result. Figure 2 As shown, a composite single-layer coating containing glassy carbon and tantalum carbide.

[0068] Example 2

[0069] The process is basically the same as in Example 1, except that the specific steps of step S3 are as follows:

[0070] S3.1 Add diethylenetriamine to the resin solution, heat to 75℃ and reflux for 3 hours to obtain an ammonia-modified resin solution, wherein the mass of diethylenetriamine is 5 wt% of the mass of the phenolic resin;

[0071] S3.2 Add acetylacetone to the tantalum solution and stir at room temperature for 45 min to obtain a complexed modified tantalum solution, wherein the mass of the diketone complexing agent is 15 wt% of the tantalum powder mass;

[0072] S3.3. Mix the ammonia-modified resin solution and the complexed tantalum solution at a mass ratio of 1:0.5, stir at room temperature for 45 min to obtain a composite solution, then coat the composite solution onto the substrate, cure at 110℃ for 1.5 h, then place it in an inert atmosphere, first heat to 750℃ for 1.5 h, then heat to 1700℃ for 2 h, and cool to room temperature to obtain the desired result. Figure 2 As shown, a composite single-layer coating containing glassy carbon and tantalum carbide.

[0073] Example 3

[0074] The process is basically the same as in Example 1, except that the specific steps of step S3 are as follows:

[0075] S3.1 Divide the resin solution into two equal portions, then coat the first portion of the resin solution directly onto the substrate surface and pre-dry at 90°C for 20 minutes to obtain a resin coating.

[0076] S3.2. Mix the second resin solution with the tantalum solution to obtain a composite solution. Then, coat the composite solution onto the resin coating and cure it at 110℃ for 1.5 hours. Next, place it in an inert atmosphere, first heat it to 750℃ for 1.5 hours, then heat it to 1700℃ for 2 hours, and finally cool it to room temperature to obtain the desired result. Figure 3 As shown, a double-layer coating structure containing a glassy carbon layer and a glassy carbon and tantalum carbide composite layer;

[0077] The mass ratio of the resin solution to the tantalum solution is 1:0.5.

[0078] Example 4

[0079] The process is basically the same as in Example 1, except that the specific steps of step S3 are as follows:

[0080] S3.1. Divide the resin solution into two equal portions. Add diethylenetriamine to the first portion of the resin solution, heat to 75°C, reflux and condense for 3 hours to obtain an ammonia-modified resin solution. Then, coat the ammonia-modified resin solution onto the substrate surface and pre-dry at 90°C for 20 minutes to obtain a resin coating. The mass of diethylenetriamine is 5 wt% of the mass of the organic resin contained in the first portion of the resin solution.

[0081] S3.2 Add acetylacetone to the tantalum solution and stir at room temperature for 45 min to obtain a complexed modified tantalum solution. Then mix it with the second resin solution and furfural to obtain a composite solution, wherein the mass of acetylacetone is 15 wt% of the mass of the tantalum source and the mass of furfural is 5 wt% of the mass of the organic resin contained in the second resin solution.

[0082] S3.3. The composite solution is coated onto the resin coating and cured at 110°C for 1.5 hours. Then, it is placed in an inert atmosphere, heated to 750°C for 1.5 hours, and then heated to 1700°C for 2 hours. After cooling to room temperature, a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer is obtained.

[0083] Comparative Example 1

[0084] It is basically the same as Example 1, except that no carbon raiser is added to the resin solution.

[0085] Comparative Example 2

[0086] It is basically the same as Example 1, except that no phase-forming promoter is added to the tantalum solution.

[0087] Comparative Example 3

[0088] It is basically the same as Example 1, except that no carbon raiser was added to the resin solution and no phase-forming accelerator was added to the tantalum solution.

[0089] Comparative Example 4

[0090] The process is basically the same as in Example 1, except that no phase-forming promoter is added to the tantalum solution. In this case, the carbonization process in step S3 is as follows: the composite solution is coated onto the substrate, cured at 110°C for 1.5 hours, and then placed in an inert atmosphere. The temperature is first raised to 1000°C for 1.5 hours, and then raised to 2000°C for 2 hours. The mixture is then cooled to room temperature to obtain a composite single-layer coating containing glassy carbon and tantalum carbide.

[0091] Performance testing

[0092] The composite coatings prepared in Examples 1-4 and Comparative Examples 1-4 were placed in a plasma etching machine with dimensions of 2cm*2cm*0.5cm. Etching was performed continuously for 10 hours under the conditions of 800W power, 5Pa chamber pressure, 50sccm Ar gas flow rate, and 10sccm Cl2 gas flow rate. Three parallel samples were used for each group, and the average weight loss per unit area (mg / cm²) was calculated for each group. 2 The calculation formula is as follows:

[0093] Weight loss per unit area = (mass of sample before etching - mass of sample after etching) / total surface area of ​​composite coating exposed to plasma environment.

[0094] The test results are shown in Table 1:

[0095] Table 1. Corrosion Resistance Test Results of Composite Coating

[0096]

[0097] As shown in Table 1, the composite coatings prepared in Examples 1-4 exhibited smaller weight loss per unit area under plasma etching conditions. Among them, Example 2 showed better results compared to Example 1. This indicates that modifying the organic resin with amine and complexing the tantalum source can further improve the corrosion resistance of the composite coating in a plasma environment. Furthermore, Example 4 also showed better results compared to Example 3. This demonstrates that using an aldehyde-based interface enhancer can effectively strengthen the interfacial bonding between the two coatings, thereby improving the corrosion resistance of the composite coating.

[0098] Further observation of Comparative Examples 1-3 reveals that, compared to Example 1, when the composite coating lacks a carbon raiser and / or a phase-forming accelerator, the corrosion resistance of the composite coating is significantly lower than that of the composite coating obtained in Example 1.

[0099] Finally, observations of Comparative Examples 2 and 4 show that, even in the absence of phase-forming promoters, increasing the carbonization temperature of the composite coating from 1700℃ to 2000℃ can also reduce the weight loss per unit area of ​​the composite coating.

[0100] The above embodiments are preferred embodiments of this application, but the implementation of this application is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this application shall be considered equivalent substitutions and shall be included within the protection scope of this application.

Claims

1. A method for preparing a composite coating for semiconductor devices, characterized in that, The preparation method includes the following steps: S1. Add organic resin and carbon raiser to alcohol solvent and mix evenly to obtain resin solution. The carbon raiser is used to increase the residual carbon content of organic resin after carbonization. S2. Add the tantalum source and the phase-forming promoter to the alcohol solvent, stir and mix to obtain a tantalum solution. The phase-forming promoter is a non-metallic phase-forming promoter used to reduce the temperature at which the tantalum source forms tantalum carbide. S3. Coat the substrate surface with resin solution and tantalum solution, heat to cure, carbonize and cool to obtain a composite coating containing glassy carbon and tantalum carbide, wherein the composite coating is a single-layer structure or a double-layer structure. The single-layer structure is a composite single-layer coating containing glassy carbon and tantalum carbide. The double-layer structure consists of a glassy carbon layer and a glassy carbon and tantalum carbide composite layer from bottom to top on one side of the substrate surface. The alcohol solvent is ethanol and / or methanol. In step S1, the mass ratio of organic resin: carbon raiser: alcohol solvent is 1:(0.1~0.3):(0.5~1). The organic resin is phenolic resin and / or epoxy resin. The carbon raiser includes at least one of nano carbon powder, carbon black, and graphene. In step S2, the mass ratio of tantalum source: phase formation promoter: alcohol solvent is (0.3~0.7):(0.05~0.2):

1. The tantalum source is tantalum powder and / or tantalum pentoxide, and the particle size of the tantalum source is 50~500nm. The phase formation promoter includes at least one of boric acid, ammonium phosphate, and urea. The carbonization temperature in step S3 is 1600~1800℃.

2. The method for preparing a composite coating for semiconductor devices according to claim 1, characterized in that, When the composite coating is a single-layer structure, step S3 includes: S3.1 Add an amino modifier to the resin solution, heat to 60-90℃, reflux and condense for 2-4 hours to obtain an amino-modified resin solution, wherein the mass of the amino modifier is 3-8 wt% of the mass of the organic resin; S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 min to obtain a complexed modified tantalum solution, wherein the mass of the diketone complexing agent is 10-20 wt% of the mass of the tantalum source; S3.3 Mix the ammonia-modified resin solution and the complex-modified tantalum solution, stir at room temperature for 30-60 min to obtain a composite solution, then coat the composite solution onto the substrate, cure at 100-120℃ for 1-2 h, then place it in an inert atmosphere, first heat to 600-900℃ for 1-2 h, then heat to 1600-1800℃ for 1-3 h, cool to room temperature to obtain a composite single-layer coating containing glassy carbon and tantalum carbide, wherein the mass ratio of ammonia-modified resin solution to complex-modified tantalum solution is 1:(0.4-0.6).

3. The method for preparing a composite coating for semiconductor devices according to claim 1, characterized in that, When the composite coating has a two-layer structure, step S3 includes: S3.1 Divide the resin solution into two equal portions, and then directly coat the first portion of the resin solution onto the substrate surface. Pre-dry at 80~100℃ for 15~30 minutes to obtain a resin coating. S3.

2. Mix the second resin solution with the tantalum solution to obtain a composite solution. Then, coat the composite solution onto the resin coating and cure it at 100~120℃ for 1~2 hours. Then, heat it to 600~900℃ for 1~2 hours and finally heat it to 1600~1800℃ for 1~3 hours. Cool it to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

4. The method for preparing a composite coating for semiconductor devices according to claim 3, characterized in that, When the composite coating has a two-layer structure, step S3 further includes: S3.1 Divide the resin solution into two equal portions. Add an amino modifier to the first portion of the resin solution, heat to 60-90℃, reflux and condense for 2-4 hours to obtain an amino-modified resin solution. Then, coat the amino-modified resin solution onto the substrate surface and pre-dry at 80-100℃ for 15-30 minutes to obtain a resin coating. The mass of the amino modifier is 3-8 wt% of the mass of the organic resin contained in the first portion of the resin solution. S3.2 Add a diketone complexing agent to the tantalum solution and stir at room temperature for 30-60 minutes to obtain a complexed modified tantalum solution. Then mix it with the second resin solution and an aldehyde-containing interface reinforcing agent to obtain a composite solution. The mass of the diketone complexing agent is 10-20 wt% of the tantalum source mass, and the mass of the aldehyde-containing interface reinforcing agent is 3-8 wt% of the organic resin contained in the second resin solution. S3.

3. Apply the composite solution to the resin coating, cure at 100~120℃ for 1~2h, then heat to 600~900℃ for 1~2h, and finally heat to 1600~1800℃ for 1~3h. Cool to room temperature to obtain a double-layer coating structure containing a glass carbon layer and a glass carbon and tantalum carbide composite layer.

5. A method for preparing a composite coating for semiconductor devices according to claim 2 or 4, characterized in that, In step S3.1, the amino modifier includes at least one of diethylenetriamine, polyethyleneimine, and triethylenetetramine, and in step S3.2, the diketone complexing agent includes at least one of acetylacetone, benzoylacetone, and furanoylacetone.

6. The method for preparing a composite coating for semiconductor devices according to claim 4, characterized in that, The aldehyde-containing interface reinforcing agent in step S3.2 includes at least one of furfural, 5-hydroxymethylfurfural, and terephthalaldehyde.

7. A composite coating for semiconductor devices, characterized in that, The composite coating for semiconductor devices is prepared by any one of the methods for preparing a composite coating for semiconductor devices according to claims 1-6.

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