Preparation method of spiral-flow type silicon carbide film

Abstract

The invention discloses a spiral-flow type silicon carbide film preparation method, and relates to the technical field of silicon carbide film preparation, and the method comprises the following steps: S1, raw material screening and preparation; s2, rotational flow film forming treatment; s3, high-temperature sintering and gas introduction; and S4, post-processing the silicon carbide film. According to the method, the biological template does not need to be impregnated, dried and carbonized, the early-stage workload of the biological template preparation method is reduced, the consumed time is shortened, the silicon carbide film is produced through continuous spin coating of the rotational flow film forming treatment, the time needed by production of the silicon carbide film is shortened, and therefore the production efficiency is improved; a large number of silicon carbide films can be prepared within a short time, the preparation efficiency is high, the surface defects and thickness of the films can be adjusted in time through two-side detection, so that the thickness and uniformity of the films are guaranteed, improvement is conducted by adjusting the heating rate, the heat preservation time and the precursor purity when it is detected that impurities are contained in the films, and the quality of the films is improved. The finished product quality of the silicon carbide film is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide film preparation, and specifically provides a method for preparing a swirling silicon carbide film. Background Art

[0002] The swirling silicon carbide film preparation method is a process technology for manufacturing silicon carbide films. The silicon carbide precursor is dissolved in a suitable organic solvent to form a uniform solution. Then, through a spin-coating device, the solution is rotated at a high speed on a substrate (such as a silicon wafer, ceramic wafer, etc.). During the rotation process, the solution flows towards the edge of the substrate under the action of centrifugal force, while the solvent gradually volatilizes, and the solute (silicon carbide precursor) spreads evenly on the surface of the substrate to form a thin film.

[0003] For example, Chinese Patent CN111573678A discloses a silicon carbide thin film forming device and a method for preparing a silicon carbide thin film, including a film spraying barrel. A top rod is slidably installed in the middle position of the upper surface of the film spraying barrel. The upper end of the top rod is provided with a first sealing cover. A pull ring is fixedly connected to the middle position of the upper surface of the first sealing cover. The lower surface of the film spraying barrel is provided with a film spraying plate, and a first sealing gasket is provided on the lower surface of the film spraying plate.

[0004] In the preparation method of the above patent, a biological template preparation method is adopted. In the early stage of preparation, a complex template preparation and treatment process is required, which increases the workload in the early stage. The soaking, drying, and carbonization processes of the biological template during preparation take a long time, reducing the preparation efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a swirling silicon carbide film to solve the problems in the above background art that the biological template preparation method requires a complex template preparation and treatment process in the early stage of preparation, increasing the workload in the early stage, and the soaking, drying, and carbonization processes of the biological template during preparation take a long time, reducing the preparation efficiency.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A method for preparing a swirling silicon carbide film, including the following steps:

[0007] S1. Raw material screening and preparation: Select a silicon carbide precursor, dissolve the precursor in an organic solvent to form a precursor solution, and add a stabilizer to the precursor solution and mix evenly;

[0008] S2. Swirling film formation treatment: Fix the pretreated substrate on a spin coater through spin coating, set the rotation speed, use a pipette to suck the precursor solution and drop it on the center of the substrate, start the spin coater, and use centrifugal force to evenly spread the solution on the surface of the substrate to form a thin film. After multiple spin coatings and drying, a sample is formed;

[0009] S3, High-temperature sintering and gas introduction: Place the spin-coated sample into a high-temperature furnace, heat up the furnace body, sinter the sample, and introduce an inert gas into the furnace during the sintering process;

[0010] S4, Post-treatment of silicon carbide film: Use chemical mechanical polishing technology, set the pressure and rotation speed, polish the film surface, clean and dry the film after polishing, and detect and store the dried film.

[0011] Preferably, in step S1, set the ceramic yield, pyrolysis temperature, and volume shrinkage during pyrolysis as screening factors to quickly screen the precursor, and the screened precursor is polycarbosilane.

[0012] Preferably, in step S1, the organic solvent is toluene. Use a magnetic stirrer to stir the weighed precursor and organic solvent to form a precursor solution, and make the concentration of the solution after preparation be 10 - 28 wt%.

[0013] Preferably, in step S2, when performing process control and parameter adjustment, it also includes the following content:

[0014] S21, Debugging of the spin coater: Set the rotation speed of the spin coater to 1000 - 3100 r / min, the rotation time to 40 - 60 seconds, the ambient temperature to 22 - 25 °C, and the humidity to 45 - 60%;

[0015] S22, Cleaning and pre-treatment of the substrate: Use an organic solvent to ultrasonically clean the substrate to remove oil and impurities on the surface, then soak the silicon wafer substrate in a hydrofluoric acid solution to remove the oxide layer on the surface, and finally place the treated substrate in a vacuum oven for drying;

[0016] S23, Spin coating process control: During multiple spin coatings, perform a drying treatment between each spin coating, check the surface of the film formed by the previous spin coating before the next spin coating until all spin coatings are completed. When drying, the temperature of the oven is 65 - 80 °C, and the drying time is 10 - 17 minutes.

[0017] Preferably, in step S23, when detecting the silicon carbide film, it includes the thickness and surface morphology of the film. Record the thickness of the film spin-coated each time measured by optical interference method. When the difference in film thickness exceeds a predetermined value, adjust the film thickness by adjusting the solution drop amount or the rotation speed and time of the spin coater. When particles or local unevenness are observed on the film surface by an optical microscope, wipe with a soft tool or locally clean with an organic solvent and then re-spin coat.

[0018] Preferably, in step S3, when the furnace body is heated, the sample is heated to 1000-1500 °C at a heating rate of 5-10 °C / min. When the temperature reaches 1000-1500 °C, heat preservation treatment is carried out for 1-3.5 hours. During heat preservation, the airtightness of the furnace body is detected, and an alarm is given in time when leakage occurs.

[0019] Preferably, in step S3, when an inert gas is introduced into the furnace, high-purity argon is introduced into the furnace at a flow rate of 10-55 ml / min. The argon enters from the bottom of the furnace and exits from the top of the furnace, forming a stable air flow in the furnace to discharge the oxygen in the furnace.

[0020] Preferably, in step S4, when chemical mechanical polishing is carried out, the polishing liquid is a silica suspension with a concentration of 10-35 wt%. The particle size of the silica particles in the polishing liquid is 60-200 nm, the polishing pressure is 0.05-0.25 MPa, the rotation speed of the polishing head is 60-200 r / min, and the polishing time is 15-60 minutes.

[0021] Preferably, in step S4, the silicon carbide film is cleaned by a multi-stage cleaning method, and ultrasonic cleaning is carried out with deionized water and organic solvents. The cleaning time is 10-30 minutes. When drying, the silicon carbide film is placed in a vacuum chamber at 60-80 °C and dried for 1.5-3 hours.

[0022] Preferably, in step S4, when detecting the dried film, the following contents are also included:

[0023] S41. Surface morphology detection: Use an optical microscope to observe whether there are obvious scratches, cracks and holes on the surface of the silicon carbide film sample, and use a scanning electron microscope to observe the microscopic damage on the surface of the silicon carbide film after polishing. When damage occurs, mark the film sample in time;

[0024] S42. Film thickness detection: Place the film sample on the detection table, and use the optical interference method to measure the spacing and number of interference fringes, so as to calculate the overall thickness of the film sample;

[0025] S43. Composition and structure detection: Through X-ray diffraction analysis, determine the crystal structure and phase composition of the film sample. By analyzing the position, intensity and shape of the diffraction peaks, the crystal form of the film sample and whether there are other impurities can be determined. If there are other impurities, mark the film sample;

[0026] S44. Detection result evaluation: Judge whether the prepared silicon carbide film sample is qualified according to multiple detection results, pick out unqualified products for marking, and store qualified products centrally.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. In the present invention, through raw material screening and preparation, the preparation of the precursor solution is realized. There is no need to impregnate, dry, and carbonize the biological template, which reduces the workload in the early stage of the biological template preparation method, shortens the time-consuming, and produces silicon carbide films through continuous spin coating by cyclone film formation treatment, which can shorten the time required for the production of silicon carbide films, thereby improving production efficiency. A larger number of silicon carbide films can be prepared in a shorter time, and thus the preparation efficiency of silicon carbide films is improved.

[0029] 2. In the present invention, after each spin coating, the surface of the generated film is inspected and the thickness is detected. When post-treating the silicon carbide film, the dried silicon carbide film is detected again. The surface morphology, thickness, composition, and structure of the film sample can be obtained. Through the two-side detection, the surface defects and thickness of the film can be adjusted in time, so as to ensure the film thickness and uniformity. When impurities are detected in the film, improvement is carried out by adjusting the heating rate, holding time, and the purity of the precursor, so as to ensure the finished product quality of the silicon carbide film. Description of the Drawings

[0030] Figure 1 It is a flowchart of a method for preparing a cyclone-type silicon carbide film according to the present invention. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Example 1: Refer to Figure 1 As shown: This embodiment provides a method for preparing a cyclone-type silicon carbide film, including the following content:

[0033] Step 1. Raw material screening and preparation: Select a silicon carbide precursor, dissolve the precursor in an organic solvent to form a precursor solution, and add a stabilizer to the precursor solution and mix evenly;

[0034] Set the ceramic yield, pyrolysis temperature, and volume shrinkage during pyrolysis as screening factors, quickly screen the precursor, the screened precursor is polycarbosilane, the organic solvent is toluene, and a magnetic stirrer is used to stir the weighed precursor and organic solvent to form a precursor solution, so that the concentration after solution preparation is 10wt%.

[0035] Step 2: Swirling film formation treatment: Fix the pretreated substrate on a spin coater through spin coating, set the rotation speed, use a pipette to suck the precursor solution and drop it on the center of the substrate, start the spin coater, and use centrifugal force to evenly spread the solution on the surface of the substrate to form a film. After multiple spin coatings and drying, a sample is formed;

[0036] When performing process control and parameter adjustment, the following contents are also included:

[0037] 21. Commissioning of the spin coater: Set the rotation speed of the spin coater to 1000 r / min, the rotation time to 40 seconds, the ambient temperature to 22 °C, and the humidity to 45%;

[0038] 22. Cleaning and pretreatment of the substrate: Ultrasonically clean the substrate with an organic solvent to remove oil stains and impurities on the surface, then soak the silicon wafer substrate in a hydrofluoric acid solution to remove the oxide layer on the surface, and finally dry the treated substrate in a vacuum oven;

[0039] 23. Spin coating process control: During multiple spin coatings, drying treatment is carried out between each spin coating. Before the next spin coating, check the surface of the film formed by the previous spin coating until all spin coatings are completed. When drying, the temperature of the oven is 65 °C and the drying time is 10 minutes. When detecting the silicon carbide film, it includes the film thickness and surface morphology. Record the film thickness of each spin coating measured by optical interference method. When the difference in film thickness exceeds the predetermined value, adjust the film thickness by adjusting the solution dropping amount or the rotation speed and time of the spin coater. When particles or local unevenness are observed on the film surface under an optical microscope, wipe it with a soft tool or locally clean it with an organic solvent and then re-spin coat.

[0040] Step 3: High-temperature sintering and gas introduction: Put the spin-coated sample into a high-temperature furnace, heat up the furnace body, sinter the sample, and introduce an inert gas into the furnace during the sintering process;

[0041] When heating up the furnace body, heat the sample to 1000 °C at a heating rate of 5 °C / min. When the temperature reaches 1000 °C, carry out a heat preservation treatment for 1 hour. When heat preserving, detect the airtightness of the furnace body and give an alarm in time in case of leakage. When introducing an inert gas into the furnace, introduce high-purity argon into the furnace at a flow rate of 10 ml / min. The argon enters from the bottom of the furnace and exits from the top of the furnace to form a stable air flow in the furnace and discharge the oxygen in the furnace.

[0042] Step 4: Post-treatment of the silicon carbide film: Use chemical mechanical polishing technology, set the pressure and rotation speed, polish the film surface, clean and dry the film after polishing, and detect and store the dried film;

[0043] When performing chemical mechanical polishing, the polishing liquid is a silica suspension with a concentration of 10 wt%, the particle size of the silica particles in the polishing liquid is 60 nm, the polishing pressure is 0.05 MPa, the rotation speed of the polishing head is 60 r / min, the polishing time is 15 minutes, the multi-stage cleaning method is used to clean the silicon carbide film, ultrasonic cleaning is carried out with deionized water and organic solvents, the cleaning time is 10 minutes, and when drying, the silicon carbide film is placed in a vacuum chamber at 60 °C for drying for 1.5 hours;

[0044] When detecting the dried film, the following contents are also included:

[0045] 41. Surface morphology detection: Use an optical microscope to observe whether there are obvious scratches, cracks and holes on the surface of the silicon carbide film sample, and use a scanning electron microscope to observe the microscopic damage on the surface of the polished silicon carbide film. When damage occurs, mark the film sample in time;

[0046] 42. Film thickness detection: Place the film sample on the detection table, and use the optical interference method to measure the spacing and number of interference fringes, so as to calculate the overall thickness of the film sample;

[0047] 43. Composition and structure detection: Determine the crystal structure and phase composition of the film sample through X-ray diffraction analysis. By analyzing the position, intensity and shape of the diffraction peaks, the crystal form of the film sample and whether there are other impurities can be determined. If there are other impurities, mark the film sample;

[0048] 44. Detection result evaluation: Judge whether the prepared silicon carbide film sample is qualified according to multiple detection results, pick out unqualified products for marking, and store qualified products centrally.

[0049] In this example, due to the low concentration of the solution, the film thickness generated after spin coating is relatively thin, and it can be quickly dried after short-time drying. The heat preservation time required for the furnace body during high-temperature sintering after the furnace body is heated can be shortened, and the charging flow rate of the inert gas can be correspondingly reduced. When performing chemical mechanical polishing, the time-consuming for cleaning using the multi-stage cleaning method is shorter, and the drying time after subsequent cleaning is also shorter.

[0050] Example Two: Refer to Figure 1 As shown: This example provides a method for preparing a cyclone silicon carbide film, including the following contents:

[0051] Step 1. Raw material screening and preparation: Select a silicon carbide precursor, dissolve the precursor in an organic solvent to form a precursor solution, and add a stabilizer to the precursor solution and mix evenly;

[0052] Set the ceramic yield, pyrolysis temperature, and volume shrinkage during pyrolysis as screening factors to quickly screen the precursors. The screened precursor is polycarbosilane, and the organic solvent is toluene. Use a magnetic stirrer to stir the weighed precursor and organic solvent to form a precursor solution, and make the concentration of the solution after preparation 18 wt%.

[0053] Step 2: Whirlpool film formation treatment: Fix the pretreated substrate on a spin coater through spin coating, set the rotation speed, use a pipette to suck the precursor solution and drop it on the center of the substrate, start the spin coater, and use centrifugal force to evenly spread the solution on the surface of the substrate to form a film. After multiple spin coatings and drying, a sample is formed;

[0054] During the process control and parameter adjustment, the following contents are also included:

[0055] 21. Debugging of the spin coater: Set the rotation speed of the spin coater to 2000 r / min, the rotation time to 50 seconds, the ambient temperature to 25 °C, and the humidity to 55%;

[0056] 22. Cleaning and pretreatment of the substrate: Use an organic solvent to ultrasonically clean the substrate to remove oil stains and impurities on the surface, then soak the silicon wafer substrate in a hydrofluoric acid solution to remove the oxide layer on the surface, and finally put the treated substrate into a vacuum oven for drying;

[0057] 23. Spin coating process control: During multiple spin coatings, drying treatment is carried out between each spin coating. Before the next spin coating, check the surface of the film formed by the previous spin coating until all spin coatings are completed. When drying, the temperature of the oven is 70 °C and the drying time is 15 minutes. When detecting the silicon carbide film, it includes the film thickness and surface morphology. Record the film thickness of each spin coating measured by optical interference method. When the difference in film thickness exceeds the predetermined value, adjust the film thickness by adjusting the solution dropping amount or the rotation speed and time of the spin coater. When particles or local unevenness are observed on the film surface by an optical microscope, wipe it with a soft tool or locally clean it with an organic solvent and then re-spin coat.

[0058] Step 3: High-temperature sintering and gas introduction: Put the spin-coated sample into a high-temperature furnace, heat the furnace body to heat the sample, and sinter the sample. During the sintering process, introduce an inert gas into the furnace;

[0059] When heating the furnace body, heat the sample to 1500 °C at a heating rate of 5 °C / min. When the temperature reaches 1500 °C, carry out a heat preservation treatment for 2 hours. During heat preservation, detect the airtightness of the furnace body and give an alarm in time when leakage occurs. When introducing an inert gas into the furnace, introduce high-purity argon into the furnace at a flow rate of 35 ml / min. The argon enters from the bottom of the furnace and exits from the top of the furnace to form a stable air flow in the furnace and discharge the oxygen in the furnace.

[0060] Step 4. Post-treatment of the silicon carbide film: Using chemical mechanical polishing technology, set the pressure and rotation speed, polish the surface of the film, clean and dry the film after polishing, and detect and store the dried film;

[0061] When performing chemical mechanical polishing, the polishing liquid is a silicon dioxide suspension with a concentration of 25 wt%, the particle size of the silicon dioxide particles in the polishing liquid is 120 nm, the polishing pressure is 0.15 MPa, the rotation speed of the polishing head is 150 r / min, the polishing time is 15 minutes. The silicon carbide film is cleaned by a multi-stage cleaning method, ultrasonically cleaned with deionized water and organic solvents, and the cleaning time is 20 minutes. When drying, the silicon carbide film is placed in a vacuum chamber at 70 °C for 2 hours;

[0062] When detecting the dried film, the following contents are also included:

[0063] 41. Surface morphology detection: Use an optical microscope to observe whether there are obvious scratches, cracks and holes on the surface of the silicon carbide film sample, and observe the microscopic damage on the surface of the polished silicon carbide film through a scanning electron microscope. When damage occurs, mark the film sample in time;

[0064] 42. Film thickness detection: Place the film sample on the detection table, and use optical interference to measure the spacing and number of interference fringes, so as to calculate the overall thickness of the film sample;

[0065] 43. Composition and structure detection: Through X-ray diffraction analysis, determine the crystal structure and phase composition of the film sample. By analyzing the position, intensity and shape of the diffraction peaks, the crystal form of the film sample and whether there are other impurities can be determined. If there are other impurities, mark the film sample;

[0066] 44. Evaluation of detection results: Judge whether the prepared silicon carbide film sample is qualified according to multiple detection results, pick out unqualified products for marking, and store qualified products centrally.

[0067] During observation, place the film sample on the stage, adjust the focal length and light source to obtain a clear image of the surface. Through observations at different magnifications, the flatness and uniformity of the film sample surface can be preliminarily evaluated. When continuous scratches are found on the film surface under an optical microscope, it indicates that the polishing parameters during the chemical mechanical polishing process are set unreasonably, and the polishing parameters need to be quickly adjusted. Set the scanning speed and scanning range of the scanning device to obtain an XRD pattern. If other peaks appear in the XRD pattern besides the characteristic diffraction peaks of silicon carbide, it may indicate that there are unreacted precursors or other impurities in the film. The heating rate and holding time can be adjusted, the protective gas can be optimized, and it can be detected whether the concentration of argon reaches more than 99.99%. At the same time, the preparation of the precursor solution can also be improved, and methods such as vacuum distillation can be used to remove low-boiling impurities and unreacted monomers in the precursor to improve the purity of the precursor, thereby reducing the content of unreacted precursors or other impurities in the subsequent produced silicon carbide film.

[0068] In this example, by detecting the surface and thickness of the thin film after each spin coating and before the next spin coating, the current spin coating situation can be quickly obtained. When the thickness of the thin film exceeds the set value, it can be adjusted by adjusting the solution dropping amount or the rotation speed and time of the spin coater to ensure the uniformity of the thickness of the multi-layer thin film. Through the detection of the thin film surface by an optical microscope, the defects of the thin film can be quickly found and remedied in time to reduce the interference of the defects on the subsequent spin coating and ensure the quality of the thin film.

[0069] Example Three: Refer to Figure 1 As shown in the figure: This example provides a method for preparing a swirl-type silicon carbide film, including the following steps:

[0070] Step 1. Raw material screening and preparation: Select a silicon carbide precursor, dissolve the precursor in an organic solvent to form a precursor solution, and add a stabilizer to the precursor solution and mix evenly;

[0071] Set the ceramic yield, pyrolysis temperature, and volume shrinkage during pyrolysis as screening factors to quickly screen the precursor. The screened precursor is polycarbosilane, the organic solvent is toluene, and a magnetic stirrer is used to stir the weighed precursor and organic solvent to form a precursor solution, so that the concentration of the solution after preparation is 28wt%.

[0072] Step 2. Swirl film formation treatment: Fix the pretreated substrate on the spin coater through spin coating, set the rotation speed, use a pipette to suck the precursor solution and drop it on the center of the substrate, start the spin coater, and use centrifugal force to evenly spread the solution on the surface of the substrate to form a thin film. After multiple spin coatings and drying, a sample is formed;

[0073] During process control and parameter adjustment, the following content is also included:

[0074] 21. Debugging of the spin coater: Set the rotation speed of the spin coater to 3100 r / min, the rotation time to 60 seconds, the ambient temperature to 25 °C, and the humidity to 60%;

[0075] 22. Cleaning and pretreatment of the substrate: Ultrasonically clean the substrate with an organic solvent to remove oil stains and impurities on the surface. Then soak the silicon wafer substrate in a hydrofluoric acid solution to remove the oxide layer on the surface. Finally, put the treated substrate into a vacuum oven for drying;

[0076] 23. Spin coating process control: During multiple spin coatings, perform a drying process between each spin coating. Check the surface of the film formed by the previous spin coating before the next spin coating until all spin coatings are completed. When drying, the temperature of the oven is 80 °C and the drying time is 17 minutes. When detecting the silicon carbide film, it includes the film thickness and surface morphology. Record the film thickness of each spin coating measured by optical interference method. When the difference in film thickness exceeds a predetermined value, adjust the film thickness by adjusting the solution dropping amount or the rotation speed and time of the spin coater. When particles or local unevenness are observed on the film surface under an optical microscope, wipe it with a soft tool or locally clean it with an organic solvent and then spin coat again.

[0077] Step 3. High-temperature sintering and gas introduction: Put the spin-coated sample into a high-temperature furnace, heat up the furnace body to sinter the sample, and introduce an inert gas into the furnace during the sintering process;

[0078] When heating up the furnace body, heat the sample to 1500 °C at a heating rate of 10 °C / min. When the temperature reaches 1500 °C, perform a heat preservation treatment for 3.5 hours. When heat preserving, detect the airtightness of the furnace body and give an alarm in time in case of leakage. When introducing an inert gas into the furnace, introduce high-purity argon into the furnace at a flow rate of 55 ml / min. The argon enters from the bottom of the furnace and exits from the top of the furnace to form a stable air flow in the furnace and discharge the oxygen in the furnace.

[0079] Step 4. Post-treatment of the silicon carbide film: Use chemical mechanical polishing technology, set the pressure and rotation speed, and polish the film surface. After polishing, clean and dry the film, and detect and store the dried film;

[0080] When performing chemical mechanical polishing, the polishing solution is a silicon dioxide suspension with a concentration of 35 wt%. The particle size of the silicon dioxide particles in the polishing solution is 200 nm, the polishing pressure is 0.25 MPa, the rotation speed of the polishing head is 200 r / min, and the polishing time is 60 minutes. Use a multi-stage cleaning method to clean the silicon carbide film, and perform ultrasonic cleaning with deionized water and an organic solvent. The cleaning time is 30 minutes. When drying, put the silicon carbide film into an 80 °C vacuum chamber and dry it for 3 hours;

[0081] When detecting the dried film, the following contents are also included:

[0082] 41. Surface topography detection: Use an optical microscope to observe whether there are obvious scratches, cracks and holes on the surface of the silicon carbide film sample, and use a scanning electron microscope to observe the microscopic damage on the surface of the polished silicon carbide film. When damage occurs, mark the film sample in time;

[0083] 42. Film thickness detection: Place the film sample on the detection stage, and use optical interference method to measure the spacing and number of interference fringes, so as to calculate the overall thickness of the film sample;

[0084] 43. Composition and structure detection: Determine the crystal structure and phase composition of the film sample through X-ray diffraction analysis. By analyzing the position, intensity and shape of the diffraction peaks, the crystal form of the film sample and whether there are other impurities can be determined. If there are other impurities, mark the film sample;

[0085] 44. Detection result evaluation: Judge whether the prepared silicon carbide film sample is qualified according to multiple detection results, pick out unqualified products for marking, and store qualified products centrally.

[0086] In this example, due to the high concentration of the solution, the film produced after spin coating is thicker, the drying time is longer, the holding time required for the furnace body during high-temperature sintering after the furnace body is heated is longer, the charging flow rate of the inert gas can be increased accordingly, and when chemical mechanical polishing is carried out, the time-consuming for cleaning using the multi-stage cleaning method is longer, and the subsequent drying time after cleaning is also extended accordingly.

[0087] In the present invention, through raw material screening and preparation, the preparation of the precursor solution is realized. There is no need to impregnate, dry, and carbonize the biological template, which reduces the workload in the early stage of the biological template preparation method and shortens the time-consuming. The silicon carbide film is produced by continuous spin coating through swirl film formation treatment, which shortens the time required for the production of the silicon carbide film, thereby improving the production efficiency. A larger number of silicon carbide films can be prepared in a shorter time, and the preparation efficiency is high. After each spin coating, the surface of the generated thin film is inspected and the thickness is measured. During the post-treatment of the silicon carbide film, the dried silicon carbide film is measured again, and the surface morphology, thickness, composition, and structure of the film sample can be obtained. Through the two-sided detection, the surface defects and thickness of the film can be adjusted in a timely manner, so as to ensure the film thickness and uniformity. When impurities are detected in the film, they are improved by adjusting the heating rate, holding time, and the purity of the precursor, so as to ensure the finished product quality of the silicon carbide film. According to the different concentrations of the precursor solution, the thickness of the thin film generated after spin coating is different. The drying time and the heating rate of the furnace body are adjusted, and the flow rate of the inert gas charged is changed to ensure the high-temperature sintering effect of the film. Through multi-stage cleaning, the polishing liquid, impurities, etc. remaining on the surface of the film after polishing treatment can be removed. After drying, water stains or impurities on the film surface can be avoided, reducing the drying during subsequent detection and ensuring the accuracy during subsequent detection.

[0088] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a cyclonic silicon carbide film, characterized in that: Includes the following: S1. Raw material screening and preparation: select a silicon carbide precursor, dissolve the precursor in an organic solvent to form a precursor solution, add a stabilizer to the precursor solution and mix well; S2, swirl film forming treatment: fix the pretreated substrate on the spin coater through spin coating, set the rotation speed, use a pipette to suck the precursor solution and drop it on the center of the substrate, start the spin coater, use centrifugal force to evenly spread the solution on the surface of the substrate to form a thin film, and form a sample after multiple spin coating and drying; S3, high temperature sintering and gas introduction: the spin-coated sample is placed in a high temperature furnace, the furnace body is heated up, and the sample is sintered. During the sintering process, an inert gas is introduced into the furnace; S4. Post-processing of silicon carbide membrane: Use chemical mechanical polishing technology to set the pressure and speed to polish the membrane surface. After polishing, the membrane is cleaned and dried, and the dried membrane is tested and stored.

2. A method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S1, the ceramic yield, pyrolysis temperature and volume shrinkage during pyrolysis are set as screening factors, and the precursor is quickly screened, and the screened precursor is polycarbosilane.

3. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S1, the organic solvent is toluene, and the weighed precursor and the organic solvent are stirred by a magnetic stirrer to form a precursor solution, and the concentration of the prepared solution is 10-28 wt %.

4. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S2, when performing process control and parameter adjustment, the following contents are also included: S21, spin coater debugging: set the spin coater rotation speed to 1000-3100r / min, the rotation time to 40-60 seconds, the ambient temperature to 22-25°C, and the humidity to 45-60%; S22, cleaning and pretreatment of the substrate: ultrasonically cleaning the substrate with an organic solvent to remove oil and impurities on the surface, then soaking the silicon wafer substrate with a hydrofluoric acid solution to remove the oxide layer on the surface, and finally placing the treated substrate in a vacuum oven to dry; S23, spin coating process control: when multiple spin coatings are performed, drying treatment is performed between each spin coating, and the surface of the film formed by the previous spin coating is checked before the next spin coating until all the spin coatings are completed. When drying, the temperature of the oven is 65-80°C, and the drying time is 10-17 minutes.

5. A method for preparing a cyclonic silicon carbide film according to claim 4, characterized in that: In step S23, when the silicon carbide film is inspected, including the thickness and surface morphology of the film, the thickness of the film is measured by optical interference method each time the film is spun on. When the difference in film thickness exceeds a predetermined value, the film thickness is adjusted by adjusting the amount of solution added or the rotation speed and time of the spin coater. When an optical microscope observes that there are particles or local unevenness on the film surface, wipe it with a soft tool or clean it locally with an organic solvent and then spin coat it again.

6. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S3, when the furnace body is heated, the sample is heated to 1000-1500°C at a heating rate of 5-10°C / min. When the temperature reaches 1000-1500°C, it is kept warm for 1-3.5 hours. During the insulation process, the sealing of the furnace body is tested and an alarm is given in time when leakage occurs.

7. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S3, when the inert gas is introduced into the furnace, high-purity argon gas is introduced into the furnace at a flow rate of 10-55 ml / min. The argon gas enters from the bottom of the furnace and is discharged from the top of the furnace, forming a stable airflow in the furnace to discharge the oxygen in the furnace.

8. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S4, during chemical mechanical polishing, the polishing liquid is a silica suspension with a concentration of 10-35wt%, a particle size of silica particles in the polishing liquid of 60-200nm, a polishing pressure of 0.05-0.25MPa, a polishing head rotation speed of 60-200r / min, and a polishing time of 15-60 minutes.

9. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S4, the silicon carbide film is cleaned by a multi-stage cleaning method, and ultrasonic cleaning is performed using deionized water and an organic solvent for 10-30 minutes. When drying, the silicon carbide film is placed in a vacuum chamber at 60-80° C. and dried for 1.5-3 hours.

10. The method for preparing a cyclonic silicon carbide film according to claim 1, characterized in that: In step S4, when the dried film is tested, the following steps are also included: S41. Surface morphology detection: Use an optical microscope to observe whether there are obvious scratches, cracks and holes on the surface of the silicon carbide film sample, and use a scanning electron microscope to observe the microscopic damage on the surface of the silicon carbide film after polishing. When damage occurs, mark the film sample in time; S42, film thickness detection: placing the film sample on the detection table, using optical interference method to measure the spacing and number of interference fringes, thereby calculating the overall thickness of the film sample; S43. Composition and structure detection: Determine the crystal structure and phase composition of the film sample by X-ray diffraction analysis. By analyzing the position, intensity and shape of the diffraction peak, the crystal form of the film sample and whether there are other impurities can be determined. If there are other impurities, the film sample is marked; S44. Evaluation of test results: Determine whether the prepared silicon carbide film samples are qualified based on multiple test results, pick out unqualified products and mark them, and store qualified products in a centralized manner.

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