Carbon-based material heating plate and preparation method thereof

Abstract

The invention discloses a carbon-based material heating disc and a preparation method thereof.The preparation method of the carbon-based material heating disc comprises the following steps that silicon carbide powder, activated carbon, graphite, a sintering aid and an adhesive are mixed and then sintered, a silicon carbide ceramic base disc is formed, then pyrolysis treatment is conducted, and graphite layers are formed on the two faces of the silicon carbide ceramic base disc; the graphite layer is etched after being polished, and a graphite electrode wire mesh is formed; depositing a diamond layer on the surface of the graphite electrode wire mesh; and after the diamond layer is polished, a heating disc support, an upper radio frequency electrode lead, a lower radio frequency electrode lead and a temperature controller are installed. The silicon carbide / graphite electrode / diamond carbon-based material heating plate is prepared by adopting the processes of preparing the graphite layer by pyrolyzing silicon carbide and forming the graphite electrode wire mesh by etching, so that the radio frequency loss is reduced, the heating efficiency is improved, the thickness consistency of the heating electrode is improved, and the service life of the heating plate is prolonged. The problems that an existing heating plate is poor in temperature uniformity, poor in corrosion resistance, low in heat dissipation efficiency and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of thin film deposition technology, specifically relating to a carbon-based material heating plate and its preparation method. Background Technology

[0002] In semiconductor manufacturing processes, atomic layer deposition (ALD) is widely used in thin film deposition. ALD processes generate plasma through integrated circuit deposition (ICP), which decomposes the precursor gas and forms a uniform thin film on the wafer surface. The sample platform, as a key component of ALD, not only heats the wafer to improve the density of the deposited film but also participates in the formation of the radio frequency (RF) circuit through its internal RF electrode mesh, influencing the plasma distribution and the uniformity of the film deposition.

[0003] Existing AlN heaters or PBN heating pads suffer from poor thermal shock resistance, resulting in poor temperature uniformity and failing to meet the temperature uniformity requirements of thin film deposition in advanced node processes. They also exhibit poor corrosion resistance; atomic layer deposition processes typically employ precursor sources and plasmas with strong corrosive properties, which easily corrode the heating pads, leading to reduced heating pad performance and affecting the quality and uniformity of the deposited film. Furthermore, at high film deposition temperatures, the heating pad needs to rapidly dissipate the heat accumulated in the film. AlN has a low thermal conductivity (approximately 200 W / m·K), resulting in low heat dissipation efficiency of the heating pad, which easily leads to heat accumulation in the film and reduces deposition quality. Finally, the heating pad electrodes, which use deposited metal wires, suffer from poor electrode thickness uniformity and are prone to failure, resulting in poor heating uniformity. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a carbon-based heating plate and its preparation method. The heating plate prepared by the present invention exhibits thermal shock resistance, corrosion resistance, and high-efficiency heat conduction, thus solving the problems of poor temperature uniformity, poor corrosion resistance, and low heat dissipation efficiency of existing heating plates. To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a carbon-based heating plate includes the following steps: Silicon carbide powder, activated carbon, graphite, sintering aids and binders are mixed and then sintered to form a silicon carbide ceramic substrate. The silicon carbide ceramic substrate is subjected to pyrolysis treatment to form a graphite layer with a thickness of 10-20 μm on both sides of the silicon carbide ceramic substrate. After polishing the graphite layer, it is etched to form a graphite electrode mesh; A diamond layer is deposited on the surface of the graphite electrode mesh; After polishing the diamond layer, the heating plate support, upper and lower radio frequency electrode leads, and temperature controller are installed.

[0005] As a preferred technical solution, the mass ratio of silicon carbide powder, activated carbon, graphite, sintering aid, and binder is (95-97):(1-2):(1-2):(0.5-2):(1-2), wherein silicon carbide powder, activated carbon, and graphite are the basic raw materials for silicon carbide ceramic substrates, which are mixed and molded to form a green body; the sintering aid is Y2O3, Al2O3, MgO, rare earth oxides, etc., and its working principle is to react with the oxide layer on the surface of silicon carbide to generate a low-melting-point glass phase or composite oxide. For example, the Y2O3-SiO2 system will generate a Y-Si-O glass phase, and Al2O3-SiO2 will generate mullite (Al6Si2O3). 13 The liquid phase can be either an aluminosilicate glass phase or a glassy phase. These glassy phases fill the gaps between SiC particles at the sintering temperature. Through the capillary action of liquid phase sintering, the particles are rearranged and the material is transported, ultimately achieving densification sintering. The role of the binder is to densify the loose green body at high temperature, thereby obtaining a high-density, high-performance ceramic substrate.

[0006] As a preferred technical solution, the oxygen content in the sintering atmosphere is 0.2wt%-0.6wt%, the sintering temperature is 1100-1700℃, and the sintering pressure is 200-300MPa. During the sintering process, the oxygen content in the sintering atmosphere and the sintering pressure need to be strictly controlled. The principle is as follows: Regarding oxygen content, the Si-C covalent bonds in silicon carbide powder are extremely strong, and the self-diffusion coefficient is extremely low, making it almost impossible to sinter densely under normal pressure; sintering aids must be added. A SiO2 oxide film (typically a few nanometers to tens of nanometers thick) spontaneously forms on the surface of the SiC powder. This oxide film is the core bridge connecting the SiC matrix and the sintering aids. The sintering aids react with the SiO2 oxide layer on the matrix surface to generate a low-melting-point glassy phase or a highly active solid phase to promote sintering. If the oxygen content is too low, the SiO2 oxide layer on the SiC surface will be reduced (for example, when the oxygen partial pressure is insufficient under an inert atmosphere, SiO2 may react with C to generate SiO gas which escapes), causing the sintering aids to lose their reactants and fail to form an effective phase to promote sintering, directly destroying the reaction substrate and ultimately hindering sintering densification. Excessive oxygen content will consume carbon elements, oxidize activated carbon and graphite, and form carbon dioxide, resulting in lower thermal conductivity, strength, and toughness. Therefore, strict control of oxygen content and temperature is necessary during sintering. Regarding pressure, if the pressure is less than 200 MPa, it will lead to low substrate density, reduced thermal conductivity, low strength and toughness, and easy cracking; if the pressure is higher than 300 MPa, the substrate is prone to breakage during sintering. Therefore, a certain pressure range needs to be controlled. This invention achieves the formation of a ceramic substrate from silicon carbide powder and densification of the substrate by strictly controlling parameters such as oxygen content, temperature, and pressure in the sintering atmosphere.

[0007] As a preferred technical solution, the adhesive is an organic molding adhesive, including at least one of water-soluble or solvent-based organic polymers such as polyvinyl alcohol (PVA), polyvinyl butyral (PVB), methyl cellulose (MC), and carboxymethyl cellulose (CMC). The adhesive provides green strength and facilitates molding; it completely decomposes and volatilizes during debinding in the sintering heating stage (typically 400-600℃), leaving no residue, and is suitable for sintering in a reducing atmosphere containing carbon (activated carbon, graphite).

[0008] As a preferred technical solution, the pyrolysis treatment process is as follows: first, maintain a temperature of 800-1000℃ for 10-20 minutes, then raise the temperature to 1400-1500℃ and hold for 20-30 minutes. Silicon carbide undergoes a pyrolysis reaction at high temperatures (usually above 1400℃). When the temperature is further increased to above 1600℃, the silicon-carbon atomic bonds in SiC gradually break, and the carbon atoms rearrange to form a graphite structure. This process requires strict control of temperature and time to ensure that the carbon atoms fully recombine and form an ordered graphite lattice.

[0009] As a preferred technical solution, the process parameters for polishing the graphite layer are: polishing rate 100-200 nm / min, polishing surface flatness 3-10 nm, and surface roughness 10-20 nm.

[0010] As a preferred technical solution, the etching is performed using inductively coupled plasma etching, with hydrogen as the etching gas, and the etching depth reaching the surface of the silicon carbide ceramic substrate; the etching rate is 10~30nm / min, and the etching linewidth is 2-10μm.

[0011] As a preferred technical solution, the deposited diamond layer is obtained by microwave plasma chemical vapor deposition or hot filament chemical vapor deposition; more preferably, microwave plasma chemical vapor deposition is used, with a process temperature of 800-1000°C and a process gas pressure of 70-90 Torr; the thickness of the diamond layer is 20-50 μm.

[0012] As a preferred technical solution, the polishing process for the diamond layer is as follows: polishing rate 1-10 nm / min, polishing surface flatness 10-20 nm, and surface roughness 3-5 nm.

[0013] The present invention also provides a carbon-based heating plate prepared by the preparation method described above.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. By using carbon-based materials such as silicon carbide / graphite electrodes / diamond that are resistant to high temperature, corrosion and have good thermal conductivity, and by controlling sintering aids and sintering process, the heating plate achieves the effects of thermal shock resistance, corrosion resistance and efficient heat conduction, solving the problems of poor temperature uniformity, poor corrosion resistance and low heat dissipation efficiency of existing heating plates. 2. By adopting the process of in-situ preparation of graphite from pyrolytic silicon carbide and etching graphite electrodes, radio frequency loss was reduced, heating efficiency was improved, heating electrode thickness uniformity was improved, and a series of problems such as heating uniformity, plasma distribution uniformity, and thin film deposition uniformity were solved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the preparation method provided by the present invention.

[0016] Reference numerals: 1-Silicon carbide ceramic substrate, 2-Graphite layer, 3-Electrode mesh, 4-Diamond layer, 5-Disc holder, 6-Upper and lower RF electrode leads, 7-Temperature controller. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention. In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional methods in the prior art, and therefore will not be described in detail. The raw materials used in the present invention are all commercially available products.

[0018] Example 1 A method for preparing a carbon-based heating plate, referenced. Figure 1 This includes the following steps: The first step is to prepare a silicon carbide ceramic substrate; The silicon carbide ceramic substrate 1 is made by sintering a mixture of 95% silicon carbide powder, 1% activated carbon, 1% graphite, 1% sintering aid (Y2O3) and 2% binder (polyvinyl alcohol). The sintering process is as follows: the oxygen content in the sintering atmosphere is 0.4wt%, the sintering temperature is 1200℃, and the sintering pressure is 250MPa. The second step involves pyrolyzing the silicon carbide ceramic substrate to form graphite. The silicon carbide ceramic substrate 1 is pyrolyzed to form a graphite layer. The silicon carbide ceramic substrate 1 is placed on the graphite support of a CVD tube furnace. Argon gas is introduced as a protective gas and hydrogen gas is introduced as a reaction gas. The tube furnace is first heated to 900°C and held for 15 min. Then the temperature is increased to 1450°C and held for 25 min to complete the growth of the double-sided graphite layer 2. The thickness of the double-sided graphite layer is controlled at 15 μm.

[0019] Step 3: Polishing the graphite surface The graphite layer 2 generated by pyrolysis was polished using a wafer polishing machine at a polishing rate of 150 nm / min, with a surface smoothness of 5 nm and a surface roughness of 15 nm.

[0020] Step 4: Etching of graphite surface electrodes The graphite layer was etched using inductively coupled plasma etching (ICP-RIE) to form a specific electrode shape, resulting in a uniform and highly consistent electrode distribution, i.e., electrode mesh 3. The etching gas was hydrogen, and the etching depth reached the surface of the silicon carbide ceramic substrate. The etching rate was 20 nm / min, and the etching linewidth was 7 μm.

[0021] Step 5: Deposit a thick diamond film on the graphite surface; A diamond layer 4 was grown on the surface of electrode mesh 3 using microwave plasma chemical vapor deposition (MPCVD) to form a highly thermally conductive and insulating sample stage. The process temperature was 900°C, the process pressure was 80 Torr, and the thickness of the diamond layer 4 was 40 μm.

[0022] Step 6: Polishing the surface of the diamond layer The diamond layer 4 was polished using a diamond polishing machine at a polishing rate of 5 nm / min, achieving a surface smoothness of 15 nm and a surface roughness of 4 nm. 5. Install the heating plate support; 6. Set the upper and lower radio frequency electrode leads of the heating plate; 7. Set the heating plate temperature controller to obtain the target product.

[0023] Example 2 A method for preparing a carbon-based heating plate includes the following steps: The first step is to prepare a silicon carbide ceramic substrate; The silicon carbide ceramic substrate 1 is made by sintering a mixture of 95% silicon carbide powder, 1% activated carbon, 1% graphite, 2% sintering aid (Al2O3) and 1% binder (polyvinyl alcohol). The sintering process is as follows: the oxygen content in the sintering atmosphere is 0.6wt%, the sintering temperature is 1400℃, and the sintering pressure is 300MPa. The second step involves pyrolyzing the silicon carbide ceramic substrate to form graphite. The silicon carbide ceramic substrate 1 is pyrolyzed to form a graphite layer. The silicon carbide ceramic substrate 1 is placed on the graphite support of a CVD tube furnace. Argon gas is introduced as a protective gas and hydrogen gas is introduced as a reaction gas. The tube furnace is first heated to 1000℃ and held for 20 min. Then the temperature is increased to 1500℃ and held for 30 min to complete the growth of the double-sided graphite layer 2. The thickness of the double-sided graphite layer is controlled at 20 μm.

[0024] Step 3: Polishing the graphite surface The graphite layer 2 generated by pyrolysis was polished using a wafer polishing machine at a polishing rate of 200 nm / min, with a surface flatness of 10 nm and a surface roughness of 10 nm.

[0025] Step 4: Etching of graphite surface electrodes The graphite layer was etched using inductively coupled plasma etching (ICP-RIE) to form a specific electrode shape, resulting in a uniform and highly consistent electrode distribution, i.e., electrode mesh 3. The etching gas was hydrogen, and the etching depth reached the surface of the silicon carbide ceramic substrate. The etching rate was 30 nm / min, and the etching linewidth was 10 μm.

[0026] Step 5: Deposit a thick diamond film on the graphite surface; A diamond layer 4 was grown on the surface of electrode mesh 3 using microwave plasma chemical vapor deposition (MPCVD) to form a highly thermally conductive and insulating sample stage. The process temperature was 1000°C, the process pressure was 90 Torr, and the thickness of the diamond layer 4 was 50 μm.

[0027] Step 6: Polishing the surface of the diamond layer The diamond layer 4 was polished using a diamond polishing machine at a polishing rate of nm / min, achieving a surface smoothness of 15 nm and a surface roughness of 4 nm. 5. Install the heating plate support; 6. Set the upper and lower radio frequency electrode leads of the heating plate; 7. Set the heating plate temperature controller to obtain the target product.

[0028] Example 3 A method for preparing a carbon-based heating plate includes the following steps: The first step is to prepare a silicon carbide ceramic substrate; The silicon carbide ceramic substrate 1 is made by sintering a mixture of 96% silicon carbide powder, 1% activated carbon, 1.5% graphite, 0.5% sintering aid (Al2O3) and 1% binder (polyvinyl alcohol (PVA)). The sintering process is as follows: the oxygen content in the sintering atmosphere is 0.4wt%, the sintering temperature is 1600℃, and the sintering pressure is 250MPa. The second step involves pyrolyzing the silicon carbide ceramic substrate to form graphite. The silicon carbide ceramic substrate 1 is pyrolyzed to form a graphite layer. The silicon carbide ceramic substrate 1 is placed on the graphite support of a CVD tube furnace. Argon gas is introduced as a protective gas and hydrogen gas is introduced as a reaction gas. The tube furnace is first heated to 900°C and held for 15 min. Then the temperature is increased to 1450°C and held for 25 min to complete the growth of the double-sided graphite layer 2. The thickness of the double-sided graphite layer is controlled at 15 μm.

[0029] Step 3: Polishing the graphite surface The graphite layer 2 generated by pyrolysis was polished using a wafer polishing machine at a polishing rate of 150 nm / min, with a surface smoothness of 5 nm and a surface roughness of 15 nm.

[0030] Step 4: Etching of graphite surface electrodes The graphite layer was etched using inductively coupled plasma etching (ICP-RIE) to form a specific electrode shape, resulting in a uniform and highly consistent electrode distribution, i.e., electrode mesh 3. The etching gas was hydrogen, and the etching depth reached the surface of the silicon carbide ceramic substrate. The etching rate was 20 nm / min, and the etching linewidth was 7 μm.

[0031] Step 5: Deposit a thick diamond film on the graphite surface; A diamond layer 4 was grown on the surface of electrode mesh 3 using microwave plasma chemical vapor deposition (MPCVD) to form a highly thermally conductive and insulating sample stage. The process temperature was 900°C, the process pressure was 80 Torr, and the thickness of the diamond layer 4 was 40 μm.

[0032] Step 6: Polishing the surface of the diamond layer The diamond layer 4 was polished using a diamond polishing machine at a polishing rate of 5 nm / min, achieving a surface smoothness of 15 nm and a surface roughness of 4 nm. 5. Install the heating plate support; 6. Set the upper and lower radio frequency electrode leads of the heating plate; 7. Set the heating plate temperature controller to obtain the target product.

[0033] Comparative Example 1 Compared with Example 1, the only difference in the comparative example is that the pressure in the sintering process in step one is different, while the other processes are the same as in Example 1; the sintering pressure in comparative example 1 is 150 MPa.

[0034] Comparative Example 2 Compared with Example 2, the only difference in the comparative example is that the oxygen content in the sintering process in step one is different, while the other processes are the same as in Example 2; the oxygen content in the sintering process in comparative example 2 is 1 wt%.

[0035] Performance Test Results and Analysis To further illustrate the beneficial technical effects of the carbon-based heating plates involved in the various embodiments of the present invention, the thermal shock resistance, corrosion resistance, thermal conductivity, radio frequency loss, heating efficiency, and heating electrode thickness consistency performance of each product were tested in accordance with the current national standards of my country. The test results are shown in Table 1.

[0036] Table 1 Performance test results of carbon-based material heating plates

[0037] As shown in Table 1, Examples 1-3, which use set sintering pressure and set sintering oxygen content, exhibit significantly better overall performance than Comparative Examples 1-2. Compared to Example 1, Comparative Example 1 (sintering pressure 150 MPa) has a lower substrate density, reduced thermal conductivity, and lower strength and toughness due to the pressure being less than 200 MPa. Consequently, the heating plate's thermal shock resistance, corrosion resistance, and thermal conductivity are significantly reduced. Compared to Example 2, Comparative Example 2 (oxygen content of 1 wt% during sintering) has a lower thermal conductivity, reduced strength and toughness, significantly increased radio frequency loss, and significantly reduced heating efficiency due to the high oxygen content consuming carbon elements, oxidizing activated carbon and graphite, and forming carbon dioxide. Furthermore, the performance of the examples shows a gradient improvement with optimization of the sintering temperature parameters: Example 3 (higher sintering temperature) shows improved thermal shock resistance, improved corrosion resistance, and extended heating plate life compared to Example 1 (sintering temperature 1200°C), indicating that appropriately increasing the sintering temperature can further enhance the number of cyclic thermal shocks and reduce the surface corrosion thickness.

[0038] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-based heating plate, characterized in that, Includes the following steps, Silicon carbide powder, activated carbon, graphite, sintering aids and binders are mixed and then sintered to form a silicon carbide ceramic substrate. The silicon carbide ceramic substrate is subjected to pyrolysis treatment to form graphite layers on both sides of the silicon carbide ceramic substrate. After polishing the graphite layer, it is etched to form a graphite electrode mesh; A diamond layer is deposited on the surface of the graphite electrode mesh; After polishing the diamond layer, the heating plate support, upper and lower radio frequency electrode leads, and temperature controller are installed.

2. The preparation method according to claim 1, characterized in that, The mass ratio of silicon carbide powder, activated carbon, graphite, sintering aid, and binder is (95-97):(1-2):(1-2):(0.5-2):(1-2); the sintering aid is at least one of Y2O3, Al2O3, MgO, and rare earth oxides; the binder is at least one of polyvinyl alcohol, polyvinyl butyral, methylcellulose, and carboxymethylcellulose.

3. The preparation method according to claim 1, characterized in that, The oxygen content in the sintering atmosphere is 0.2wt%-0.6wt%, the sintering temperature is 1100-1700℃, and the sintering pressure is 200-300MPa.

4. The preparation method according to claim 1, characterized in that, The pyrolysis process is as follows: first, maintain the temperature at 800-1000℃ for 10-20 minutes, then raise the temperature to 1400-1500℃ and hold for 20-30 minutes.

5. The preparation method according to claim 1, characterized in that, The thickness of the graphite layer is 10-20 μm.

6. The preparation method according to claim 1, characterized in that, The process parameters for polishing the graphite layer are: polishing rate 100-200 nm / min, polishing surface flatness 3-10 nm, and surface roughness 10-20 nm.

7. The preparation method according to claim 1, characterized in that, The etching is performed using inductively coupled plasma etching, with hydrogen as the etching gas, and the etching depth reaches the surface of the silicon carbide ceramic substrate. The etching rate is 10~30nm / min, and the etching linewidth is 2-10μm.

8. The preparation method according to claim 1, characterized in that, The deposited diamond layer is formed by microwave plasma chemical vapor deposition or hot filament chemical vapor deposition; the process temperature of microwave plasma chemical vapor deposition is 800-1000°C, and the process gas pressure is 70-90 Torr; the thickness of the diamond layer is 20-50 μm.

9. The preparation method according to claim 1, characterized in that, The polishing process for the diamond layer is as follows: polishing rate 1-10 nm / min, polishing surface flatness 10-20 nm, and surface roughness 3-5 nm.

10. A carbon-based heating plate prepared by any one of claims 1 to 9.

Images