Automated chemical vapor deposition equipment capable of atomic precision manufacturing

Abstract

The present invention discloses an automated chemical vapor deposition (CVD) system capable of atomic precision manufacturing, belonging to the technical field of atomic layer deposition. This system integrates pressure, temperature, and flow systems to achieve fully automated control of the chemical vapor deposition process. By implementing empirical valve opening in pressure control, the target pressure can be quickly approached, significantly improving response time. A non-continuous angle control algorithm has also been designed, enabling high control accuracy even for large pressure control in the chemical vapor deposition process. Furthermore, this system is also equipped with an in-situ characterization system, which uses corresponding devices to realize real-time detection of the deposition status of samples during the chemical deposition process. Furthermore, this application also features a furnace body moving rail, which allows the furnace body to move after the production process is completed and waiting for heat dissipation, completely exposing the heated area to air, maximizing heat dissipation efficiency and improving overall production efficiency.

Description

[Technical Field]

[0001] This invention relates to an automated chemical vapor deposition (QV) deposition system capable of manufacturing with atomic precision, and belongs to the field of atomic layer deposition technology. [Background technology]

[0002] With the continuous development of modern scientific research, the precision of processing methods and manufacturing technologies has also continuously improved. The field of mechanical engineering has begun to merge and intersect with fields such as chemistry, physics, and materials science, giving rise to a new frontier field: "atomic-scale and near-atomic-scale manufacturing."

[0003] So-called atomic-scale and near-atomic-scale manufacturing refers to manufacturing and processing processes at the atomic and near-atomic scales. Atomic layer deposition (ALD) is a method that uses atomic layer deposition to grow films layer by layer on the surface of a material. Because it allows for high-precision control of film thickness and material composition, it is widely used in fields such as microelectronics, optoelectronics, and touchscreens. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] To achieve precise control of deposited samples, the corresponding CVD equipment needs to be equipped with high-precision temperature, pressure, and flow rate control systems. However, many of the CVD systems currently used in China are assembled from instruments and components from different manufacturers, requiring manual adjustment and intervention of each system's parameters, resulting in a low degree of automation. Furthermore, the control accuracy is also dependent on human intervention, leading to reduced precision and making it impossible to meet the requirements of atomic layer deposition. [Means for solving the problem]

[0005] To solve the above problems, the present invention provides an automated chemical vapor deposition (CVM) deposition system capable of atomic precision manufacturing. The system includes a pressure system, a temperature system, a flow rate system, and a control system, the pressure system, temperature system, and flow rate system all connected to the control system, and the control system achieves fully automated control of the system based on real-time feedback data from the pressure system, temperature system, and flow rate system.

[0006] Preferably, the pressure system includes a valve, a stepping motor, and a pressure sensor located in a quartz tube of the CVD apparatus, the pressure sensor being used to take real-time pressure values ​​so that the control system adjusts the valve opening of the extraction piping in real time based on the pressure value in the quartz tube to reach a target pressure, which is the pressure value required at each stage of the film deposition process. The valve is connected to a vacuum pipe, and the stepping motor drives the valve to open and close in constant step angles, and assuming a constant gas flow rate, the magnitude of the pressure can be directly controlled by controlling the magnitude of the valve opening of the vacuum pipe. When the control system adjusts the valve opening of the extraction piping in real time, it employs a periodic discontinuous angle control algorithm or a continuous angle control algorithm based on the relationship between the pressure value and a preset pressure threshold to automatically control the pressure.

[0007] Preferably, the control system adjusting the valve opening of the extraction piping in real time based on the pressure value to reach the target pressure includes the following: Under conditions where flow rate and temperature are constant, the valve is adjusted to the empirically experienced opening at the target pressure based on the angle-pressure empirical curve, which is a curve showing how the pressure inside the quartz tube changes with the valve opening.

[0008] The method for obtaining an empirical angle-pressure curve involves maintaining a constant temperature and gas flow rate while measuring the pressure change associated with a change in the opening of a butterfly valve.

[0009] The method for obtaining an empirical curve of angle and velocity includes maintaining a constant temperature and a constant gas flow rate, setting a sampling period, and measuring the change in pressure change rate associated with a change in the opening degree of a butterfly valve within the sampling period.

[0010] Based on the angle-pressure empirical curve, the butterfly valve opening, which corresponds to the empirically observed opening that corresponds to the target pressure required at each stage of the film deposition process, is determined. By quickly opening the butterfly valve to the empirically observed opening, the actual pressure value can be rapidly brought closer to the target pressure value.

[0011] The system compares the pressure value with a preset pressure threshold. If the pressure value is greater than or equal to the pressure threshold, it employs a periodic discontinuous angle control algorithm to automatically control the pressure. Otherwise, it employs a continuous angle control algorithm to automatically control the pressure.

[0012] In actual sedimentation processes, pressure is a certain numerical value P. θ Once it reaches this point, the time required to increase the pressure by a certain amount becomes much longer than the time required to decrease it by the same amount. θ A pressure threshold is set, and different control algorithms are employed for pressure values ​​greater than and less than this pressure threshold to perform control.

[0013] Preferably, the logic of the periodic discontinuous angle control algorithm is as follows: Pressure sampling period ΔT and pressure change rate threshold ΔP θ The pressure change rate threshold ΔP is set. θ This is determined based on an empirical angle-velocity curve. The empirical angle-velocity curve is a curve that shows how the rate of pressure change in a quartz tube changes with the opening of a butterfly valve, under conditions where the flow rate and temperature are constant. From the trend of the empirical angle-velocity curve, it can be seen that as the opening of the butterfly valve changes, the rate of pressure change gradually increases, and then decreases after reaching a certain value, meaning that there is a maximum value for the rate of pressure change.

[0014] S1: Obtain the pressure change rate ΔP within the pressure sampling period ΔT. S2: Determine whether the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ : S2.1; When the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ Based on the degree to which the absolute value of the pressure change rate further exceeds the set pressure change rate threshold and the positive or negative value of the pressure change rate ΔP, determine the step angle and direction of the valve. Divide the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold into multiple stages. For example, 1) When the absolute value of the pressure change rate ΔP exceeds 50% of ΔP max and ΔP is a positive value, step the butterfly valve in the positive direction by the step angle α1. 2) When the absolute value of the pressure change rate ΔP exceeds 70% of ΔP max and ΔP is a positive value, step the butterfly valve in the positive direction by the step angle α2. 3) When the absolute value of the pressure change rate ΔP exceeds 80% of ΔP max and ΔP is a positive value, step the butterfly valve in the positive direction by the step angle α3. The above step angles satisfy α1 < α2 < α3.

[0015] In the above three cases, if the pressure change rate ΔP is a negative value, step the butterfly valve in the reverse direction by the corresponding step angle. Here, the positive direction step of the butterfly valve refers to the opening operation, and the reverse direction step refers to the closing operation.

[0016] S2.2; When the absolute value of the pressure change rate ΔP does not exceed the set pressure change rate threshold ΔP θ further collect the current pressure value P, determine the magnitude relationship between the current pressure value P and the target pressure and the positive or negative of the pressure change rate ΔP, and further determine the step angle and direction of the valve. 1) If the current pressure P is less than the target pressure and the pressure change rate ΔP is positive, the butterfly valve is either kept at its current angle or stepped in the reverse direction by a step angle α4. 2) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is negative, the system is stepped in the reverse direction by a step angle α5. 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is positive, the system is stepped in the positive direction by a step angle α4. 4) If the current pressure P is greater than the target pressure and the pressure change rate ΔP is negative, the butterfly valve is either kept at its current angle or stepped in the positive direction by a step angle α5. Here, α4 < α5, and α4 ≪ α1, α5 ≪ α1.

[0017] S3: Read the pressure after adjusting the valve opening, calculate the difference from the target pressure, and determine if the difference is within the margin of error. If the difference is within the margin of error, maintain the current valve opening. If the difference is not within the margin of error, continue sampling the rate of pressure change within the next cycle and repeat the above process.

[0018] Preferably, the temperature system includes a temperature sensor, which is provided on the outer wall of a quartz tube corresponding to the deposition sample location and is used to obtain the temperature of the deposition sample location in real time, and the control system adjusts the heating power and heating time to bring the temperature inside the quartz tube to a target temperature value based on the real-time temperature fed back from the temperature sensor.

[0019] Preferably, the equipment further includes an in-situ characterization system including an absorption spectrum detector and a spectral shift / optical path calibration device, wherein the absorption spectrum detector enables online in-situ characterization of the deposited sample. The spectral detection device includes a light source, a light-emitting device, a light-receiving device, and a spectrometer connected to the light-receiving device. The spectral movement and optical path calibration device includes two moving rails, with the light emitter and light receiver each mounted on two moving rails. The moving rails enable the movement of the light emitter and light receiver, allowing for online in-situ characterization of a sample at any position within the quartz tube.

[0020] The tubular CVD apparatus includes a furnace body, a quartz tube, and a quartz boat for placing a deposited sample inside the quartz tube. To enable light emitted from a light-emitting device to pass through the furnace body and to achieve online in-situ characterization of a sample at any position within the quartz tube, the furnace body of this application is provided with two symmetrical light-passing slots parallel to the quartz tube, and the width of the light-passing slots is set so that light emitted from the light-emitting device and light received by the light-receiving device can pass through completely. The two light-passing slots are symmetrical along the axial centerline of the quartz tube, and the two moving rails of the spectral movement / optical path calibration device are located outside the furnace body at positions corresponding to the two light-passing slots, respectively, so that the light-emitting device and the light-receiving device can move linearly along the axial direction of the quartz tube, enabling in-situ detection of a sample at any position within the quartz tube. Light emitted from the light-emitting device passes through the light-transmitting slot, through the quartz tube and the sediment sample inside it, and reaches the light-receiving device. Furthermore, spectral analysis is performed by a spectrometer based on the received light source, enabling in-situ detection of the sediment sample.

[0021] Preferably, the spectral shifting and optical path calibration device further includes four stepping motors and a four-axis optical path automatic calibration system is provided. The four stepping motors are denoted as the first transverse stepping motor, the first longitudinal stepping motor, the second transverse stepping motor, and the second longitudinal stepping motor. Here, the first transverse stepping motor and the first longitudinal stepping motor drive a ball screw and a moving rail to achieve positioning of the light-emitting device in the horizontal plane, while the second transverse stepping motor and the second longitudinal stepping motor are used to control the rotation of the light-emitting device in the horizontal and vertical planes.

[0022] Preferably, the 4-axis optical path automatic calibration system employs a single-chip microcontroller or PLC controller to control the stepping motors. By setting the PWM wave for each motor, its rotation speed can be controlled, and by comparing the intensity of the reflected light, the optical path can be finely adjusted so that the received light intensity is maximized, facilitating subsequent spectral analysis.

[0023] Preferably, the light source is a white light source, has a continuous spectrum, and its wavelength range includes at least 200 to 1050 nm. Here, in the ultraviolet band where the wavelength is in the range of 250 nm to 400 nm, the luminous flux > 10 mW / mm 2 It has an sr·nm property, and the light source has strong collimation, allowing the spot to be focused into a 1mm diameter circle at a distance of 0.5m or less.

[0024] Preferably, the equipment further includes furnace body movement rails for moving the furnace body. Moving the furnace body after the stacking is complete allows the heated area of ​​the quartz tubes to be fully exposed to the air, maximizing heat dissipation efficiency and improving overall production efficiency.

[0025] Preferably, the flow system includes a flow meter, and the control system controls the flow meter based on set flow parameters to achieve the effects of flow control.

[0026] Preferably, the equipment further includes a touchscreen, via which a technician can set corresponding parameters. [Effects of the Invention]

[0027] The beneficial effects of this invention are as follows: By providing a CVD apparatus that integrates pressure, temperature, and flow rate systems, fully automated control of the chemical vapor deposition process is achieved. Specifically, in pressure control, by introducing the empirical opening of valves, the target pressure can be approached quickly, and the response time is greatly improved. Furthermore, by designing a discontinuous angle control algorithm, high control accuracy can be achieved even for large pressure controls in the chemical vapor deposition process. In temperature control, the effect of temperature control is achieved by using a PID control algorithm to control the on / off state of solid-state relays. In addition, the apparatus is equipped with an in-situ characteristic evaluation system, which enables real-time detection of the sample deposition status in the chemical deposition process using the corresponding device. By combining this with changes in the system's temperature and pressure, it is possible to further understand the rules by which the sample or reaction system changes in response to environmental changes such as temperature and pressure, thereby determining the optimal deposition conditions. Furthermore, this application is equipped with furnace body movement rails, which allow the furnace body to be moved when the production process is complete and heat dissipation is awaiting, thereby completely exposing the heated area to air, maximizing heat dissipation efficiency, and improving overall production efficiency. [Brief explanation of the drawing]

[0028] To more clearly explain the technical concepts in the embodiments of the present invention, the following is a brief introduction of the drawings necessary for describing the embodiments. It is clear that the drawings in the following description are only a part of the embodiments of the present invention, and those skilled in the art can obtain other drawings based on these without any creative effort. [Figure 1] This is a schematic diagram showing the positional relationship between the furnace body movement rail and the furnace body in a CVD apparatus according to one embodiment of the present invention, where reference numeral 1 denotes the furnace body, reference numeral 2 denotes the quartz tube, and reference numeral 12 denotes the furnace body movement rail. [Figure 2] This is a flowchart illustrating a method for automatically controlling pressure using a control system according to one embodiment of the present invention. [Figure 3] This diagram shows the empirical angle-pressure curve corresponding to the case where the gas flow rate is 0 at room temperature (25°C). [Figure 4] This figure shows the empirical angle-velocity curve corresponding to the case where the gas flow rate is 0 at room temperature (25°C). [Figure 5] This is a schematic diagram of an in-situ characterization system in a CVD apparatus according to one embodiment of the present invention, where 1 is the furnace body, 2 is the quartz tube, 3 is the quartz boat, 4 is the deposited sample, 5 is the light-passing slot, 6 is the light source, 7 is the light-emitting device, 8 is the light-receiving device, 9 is the spectrometer, 10 is the rail, and 11 is the stepping motor. [Figure 6] This is a schematic three-dimensional diagram of a four-axis optical path calibration system for an in-situ characteristic evaluation system in a CVD apparatus according to one embodiment of the present invention, where reference numeral 1101 indicates the first lateral stepping motor, reference numeral 1102 indicates the first longitudinal stepping motor, reference numeral 1103 indicates the second longitudinal stepping motor, and reference numeral 1104 indicates the second lateral stepping motor. [Modes for carrying out the invention]

[0029] To further clarify the object, technical proposal and advantages of the present invention, embodiments of the present invention will be described in more detail below with reference to the drawings.

[0030] Example 1 This embodiment provides an automated chemical vapor deposition (QV) deposition system capable of atomic precision manufacturing, including a pressure system, temperature system, flow rate system, and control system. The pressure system, temperature system, and flow rate system are all connected to the control system, which provides fully automated control of the equipment based on real-time feedback data from the pressure system, temperature system, and flow rate system. The equipment is equipped with a display touchscreen, allowing technicians to directly set corresponding deposition parameters, and the control system can complete the entire deposition process based on the set parameters. Furthermore, to facilitate early cooling after deposition is complete, this application includes a furnace body movement rail 12. As shown in Figure 1, by moving the furnace body during the heat dissipation phase, the heated area of ​​the quartz tube 2 is completely exposed to the air, maximizing heat dissipation efficiency and improving overall production efficiency.

[0031] The following sections will be explained in order. (1) The pressure system includes a valve, a stepping motor, and a pressure sensor located inside the quartz tube of the CVD apparatus. The pressure sensor is used to collect pressure values ​​in real time so that the control system can adjust the valve opening of the extraction piping in real time based on the pressure value inside the quartz tube to reach the target pressure. The valve is connected to the vacuum piping, and the stepping motor is used to open and close the valve in a constant step angle. When the control system adjusts the valve opening of the extraction piping in real time, it employs either a periodic discontinuous angle control algorithm or a continuous angle control algorithm based on the relationship between the pressure value and a preset pressure threshold to automatically control the pressure. For a specific control flow, please refer to Figure 2, where Algorithm 1 is a periodic discontinuous angle control algorithm and Algorithm 2 is a continuous angle control algorithm.

[0032] When the control system adjusts the valve opening of the extraction piping in real time, it first adjusts the valve to the empirically experienced opening for the target pressure based on an empirically experienced angle-pressure curve. The empirically experienced angle-pressure curve is a curve that shows how the pressure inside the quartz tube changes with valve opening under conditions where the flow rate and temperature are constant. By acquiring empirically experienced angle-pressure curves under different temperature and flow rate conditions in advance, in a specific deposition process, the valve opening corresponding to the target pressure, i.e., the empirically experienced opening, can be determined simply by acquiring the current gas flow rate and temperature. Figure 3 shows the empirically experienced angle-pressure curve corresponding to the case where the gas flow rate is 0 at room temperature of 25°C.

[0033] In actual sedimentation processes, the pressure range within the quartz tube is wide, and it is thought that it can vary from vacuum to atmospheric pressure, and the pressure is a numerical value P. θ Once it reaches this point, the time required to increase the pressure by a certain amount becomes much longer than the time required to decrease it by the same amount. θ For greater pressure, P θ A different pressure control method is required compared to the case of lower pressures. Therefore, in this application, the pressure threshold P θ This is pre-set (specifically by the engineer, the pressure threshold P θ The value of P can be determined, for example, θ (=20kPa). Current pressure value and preset pressure threshold P θ Based on the relative magnitudes of these factors, a periodic discontinuous angle control algorithm or a continuous angle control algorithm is employed to automatically control the pressure. Specifically, this is as follows: When the pressure value is above the pressure threshold, a periodic discontinuous angle control algorithm is used to automatically control the pressure; otherwise, a continuous angle control algorithm is used to automatically control the pressure. Here, the PID control algorithm, which is the continuous angle control algorithm, is a relatively mature control algorithm in the industrial field. Refer to the introduction of Chinese patents CN112695297A "Method for controlling chamber pressure in semiconductor processes" or CN116931610A "High-speed response method and apparatus for pressure control," and a detailed explanation is omitted here. The logic of the periodic discontinuous angle control algorithm is as follows. Pressure sampling period ΔT and pressure change rate threshold ΔP θ The pressure change rate threshold ΔP is set. θ This is determined according to the empirical angle-velocity curve. The empirical angle-velocity curve is a curve that shows how the rate of pressure change in a quartz tube changes with valve opening under conditions where flow rate and temperature are constant. From the actual empirical angle-velocity curve, as the valve opening increases, the rate of pressure change has a maximum value ΔP. max It can be seen that there is a pressure change rate threshold ΔP. θ ΔP θ =K*ΔP max It can be set to K=0.5~0.8, and the specific value is determined by the engineer. Figure 4 is a diagram of the empirical angle-velocity curve corresponding to the case of zero gas flow rate at room temperature of 25°C, and the maximum value of the pressure change rate ΔP at 25°C with zero gas flow rate. max It can be seen that this is equal to 0.38 kPa / s.

[0034] S1: Obtain the rate of pressure change ΔP within the pressure sampling period ΔT. S2: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP. θ Determine whether it exceeds a certain value. S2.1: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP. θIf it exceeds a certain value, the step angle and direction of the valve are determined based on the degree to which the absolute value of the pressure change rate exceeds a set pressure change rate threshold, and the positive or negative value of the pressure change rate ΔP. Specifically, the degree to which the absolute value of the pressure change rate exceeds a set pressure change rate threshold can be divided into multiple stages, for example, 1) The absolute value of the pressure change rate ΔP is ΔP max If the value exceeds 50% and ΔP is positive, the butterfly valve is stepped in the positive direction by a step angle α1. 2) The absolute value of the pressure change rate ΔP is ΔP max If the value exceeds 70% and ΔP is positive, the butterfly valve is stepped in the positive direction by a step angle α2. 3) The absolute value of the pressure change rate ΔP is ΔP max If the value exceeds 80% and ΔP is positive, the butterfly valve is stepped in the positive direction by a step angle α3. The above step angles satisfy α1 < α2 < α3.

[0035] In the three cases described above, if the pressure change rate ΔP is negative, the butterfly valve is stepped in the reverse direction by the corresponding step angle. Here, a forward step of the butterfly valve refers to the opening operation, and a reverse step refers to the closing operation.

[0036] In one embodiment, α1 = 0.05°, α2 = 0.1°, and α3 = 0.15°.

[0037] S2.2: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP. θ If the pressure does not exceed the target pressure, the current pressure P is further measured, the relationship between the current pressure P and the target pressure and the sign of the pressure change rate ΔP are determined, and the step angle and direction of the valve are then determined. Specifically, 1) If the current pressure P is less than the target pressure and the pressure change rate ΔP is positive, the butterfly valve is either kept at its current angle or stepped in the reverse direction by a step angle α4. 2) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is negative, the system is stepped in the reverse direction by a step angle α5. 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is positive, the system is stepped in the positive direction by a step angle α4. 4) If the current pressure P is greater than the target pressure and the pressure change rate ΔP is negative, the butterfly valve is either kept at its current angle or stepped in the positive direction by a step angle α5. Here, α4 < α5, and α4 ≪ α1, α5 ≪ α1.

[0038] In one embodiment, α4 = 0.001° and α5 = 0.002°. S3: Read the pressure inside the quartz tube after the above adjustments, calculate the difference from the target pressure, and determine if the difference is within the margin of error. If the difference is within the margin of error, maintain the current valve opening. If the difference is not within the margin of error, continue sampling the rate of pressure change within the next cycle and repeat the above process.

[0039] (2) The temperature system includes a temperature sensor, which is installed on the outer wall of the quartz tube corresponding to the location of the deposited sample and is used to obtain the temperature of the deposited sample location in real time. Based on the real-time temperature fed back from the temperature sensor, the control system adjusts the heating power and heating time to bring the temperature inside the quartz tube to a target temperature value.

[0040] (3) The flow system includes a flow meter, and the control system controls the flow meter based on set flow parameters to achieve the effect of flow control.

[0041] (4) To enable real-time monitoring of the chemical vapor deposition process for material manufacturing at the atomic level, the apparatus provided in the embodiment of this application further includes an in-situ characterization system including an absorption spectrum detector and a spectral shift / optical path calibration apparatus. As shown in Figure 5, the absorption spectrum detector includes a light source 6, a light emitter 7, a light receiver 8, and a spectrometer 9 connected to the light receiver 8. The spectral shift / optical path calibration apparatus includes two moving rails 10 and corresponding stepping motors 11, with the light emitter 7 and the light receiver 8 each mounted on the two moving rails 10. The tubular CVD apparatus includes a furnace body 1, a quartz tube 2, and a quartz boat 3 for placing a deposition sample inside the quartz tube 2. The furnace body 1 has two symmetrical light-passing slots 5 parallel to the quartz tube. The two light-passing slots 5 are symmetrical along the axial centerline of the quartz tube, and the two moving rails 10 of the spectral moving device are located outside the furnace body 1, corresponding to the two light-passing slots 5, allowing the light-emitting device 7 and the light-receiving device 8 to move linearly along the axial direction of the quartz tube 2. Light emitted from the light-emitting device 7 passes through the light-passing slots 5, through the quartz tube 2 and the deposited sample 4 inside it, and reaches the light-receiving device 8. Furthermore, spectral analysis is performed by the spectrometer 9 based on the received light source, enabling in-situ detection of the deposited sample 4.

[0042] The length of the light-passing slot 5 can be determined according to the actual situation, and its width is set so that the light emitted from the light-emitting device 7 and the light received by the light-receiving device 8 can pass through completely.

[0043] To ensure that the light emitted from the light-emitting device 7 is accurately received by the light-receiving device 8, a four-axis optical path calibration system is designed in this application, and the optical path between the light-emitting device 7 and the light-receiving device 8 is calibrated by four stepping motors 11. As shown in Figure 6, the first lateral stepping motor 1101 and the first vertical stepping motor 1102 are used for coarse adjustment, and the second lateral stepping motor 1104 and the second vertical stepping motor 1103 are used for fine adjustment. The first lateral stepping motor 1101 and the first vertical stepping motor 1102 achieve positioning in the horizontal plane by driving a ball screw and a slide rail, and the second lateral stepping motor 1104 and the second vertical stepping motor 1103 are used to control the rotation of the light-emitting device 7 in the horizontal and vertical planes. The calibration of the light source can be achieved by simply combining the four motors. Furthermore, the control of the four stepping motors is realized by an STM32 single-chip microcontroller, and the rotation speed can be controlled by setting the PWM wave for each motor. By comparing the intensity of the reflected light, the optical path can be finely adjusted so that the received light intensity is maximized, making subsequent spectral analysis easier.

[0044] Light source 6 satisfies the following conditions. 1) The spectrum is continuous, and the wavelength range includes 200–2000 nm. 2) The overall light intensity is sufficiently strong, especially in the ultraviolet band (200nm-400nm), with a luminous flux of >10mW / mm². 2 It is sr-nm. 3) The collimation is strong, and the spot can be focused into a circle with a diameter of 1 mm at a distance of 0.5 m or less.

[0045] Considering the high-temperature environment of the deposition process, the furnace body is red, which has a certain effect on the light source signal. Therefore, direct analysis based on the spectral signal will result in a certain degree of error. In this application, a more accurate analytical result is obtained by first acquiring a temperature gradient compensated spectrum and then performing corresponding compensation on the obtained spectrum before analysis. Specifically, In step 1, the sample is not left unattended, but the optical path is passed through the quartz tube and quartz boat to the photodetector 8, i.e., the spectrometer detector, and one spectrum is obtained as the initial spectrum.

[0046] In step 2, the temperature is gradually increased to 900°C, and a spectrum is obtained once for every ΔT from 100°C. The difference from the initial spectrum is calculated to obtain the red light compensation spectrum at different temperature gradients. Here, the specific value of ΔT can be determined by the engineer according to the actual situation, for example, ΔT = 10°C or ΔT = 25°C.

[0047] Subsequently, by subtracting the corresponding red light compensation spectrum from the spectrum acquired in real time at a certain temperature during the deposition process, a more accurate absorption spectrum can be obtained as the final spectrum.

[0048] When analyzing a substance based on its absorption spectrum, the formula for calculating its absorbance is as follows: Absorbance = log (incident light intensity / transmitted light intensity) Here, the incident light intensity is the intensity of the light emitted from the light-emitting device 7, and the transmitted light intensity is the intensity of the light received by the light-receiving device 8.

[0049] For example, before introducing the sample, the light passes through the quartz boat and quartz tube. Under room temperature conditions (25°C), no red light is present, and the transmitted light intensity at this time is denoted as L1. After the sample is introduced, the light passes through the quartz tube, quartz boat, and sample under experimental conditions. At a temperature of 800°C, red light is present. Let L2 be the transmitted light intensity at this point, and L3 be the light intensity of the red light compensation spectrum corresponding to 800°C. Then, the absorbance without compensation (measured value) A = lg(L1 / L2), and the actual value (true value) A' = lg(L1 / (L2-L3)). Therefore, the compensation value Δ of the red light compensation spectrum corresponding to 800°C. 800 =A'-A=lg(L2 / (L2-L3)).

[0050] Using the method described above, the compensation values ​​Δ1, Δ2, Δ3, ..., Δ of the red light compensation spectrum corresponding to each ΔT℃ interval from 100℃ are obtained. n To obtain.

[0051] In the subsequent deposition process, when the deposition temperature is set to 800°C, the compensation value Δ of the red light compensation spectrum corresponding to 800°C is obtained from the resulting spectrum. 800 The final spectrum is obtained by subtracting a certain value, and further analysis must be performed based on this final spectrum.

[0052] In step 3, the deposition status of the deposition process is analyzed based on the final spectrum.

[0053] In this application, the light-emitting device 7 and the light-receiving device 8 are each mounted on two moving rails 10, and because the axial length of the light-passing slots opened in the furnace body allows the light source to reach any position inside the quartz tube 2, by moving the light-emitting device 7 and the light-receiving device 8 during the deposition process, it is possible to detect a sample at any position inside the quartz tube 2 in real time and obtain the deposition status of the sample.

[0054] Existing in-situ technologies all evaluate in-situ characteristics at a single point. In this application, by synchronously moving a white light source emitter 7 and a light receiver 8, we have achieved movable in-situ characteristic evaluation within a quartz tube. This innovation will play a crucial role in exploring growth windows for new materials.

[0055] In many CVD processes, once conditions such as temperature, pressure, and carrier gas flow rate are determined, the material grows at a specific location. This location is commonly called the "growth window." Conventional experimental processes require repeated experiments at different locations and offline characterization after the experiments. As a result, roughly determining the growth window may require several to dozens of experiments, making the procedure cumbersome and time-consuming. The system and method of this application allows for arbitrary movement during the experimental process, and the growth window can be determined by characterizing the growth of the material at different locations, thus enabling the rapid acquisition of superior deposition effects.

[0056] This application provides a CVD apparatus that integrates a pressure system, a temperature system, and a flow rate system, thereby achieving fully automated control of the chemical vapor deposition process. Specifically, in pressure control, the introduction of experienced valve openings allows for rapid approach to the target pressure, significantly improving response time. Furthermore, by designing a discontinuous angle control algorithm, high control accuracy can be achieved even for large pressures in the chemical vapor deposition process. In temperature control, a PID control algorithm is employed to control the on / off state of solid-state relays, achieving the desired temperature control effect. In addition, the apparatus is equipped with an in-situ characteristic evaluation system, enabling real-time detection of the sample deposition status in the chemical deposition process using a corresponding device. By combining this with changes in the system's temperature and pressure, it is possible to further understand the rules by which the sample or reaction system changes in response to environmental changes such as temperature and pressure, thereby determining the optimal deposition conditions. Furthermore, this application provides furnace body movement rails, which allow the furnace body to be moved when the production process is complete and heat dissipation is awaiting, thereby completely exposing the heated area to air, maximizing heat dissipation efficiency, and improving overall production efficiency.

[0057] Some steps in the embodiments of the present invention can be implemented by software, and the corresponding software programs can be stored on a readable storage medium such as an optical disc or a hard disk.

[0058] The above description is merely a preferred embodiment of the present invention and does not limit it. Any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and principles of the present invention shall be within the scope of protection of the present invention.

Claims

1. An automated chemical vapor deposition (CVM) deposition system capable of achieving atomic precision manufacturing, The system includes a pressure system, a temperature system, a flow rate system, and a control system, the pressure system, temperature system, and flow rate system all connected to the control system, and the control system achieves fully automatic control of the equipment based on real-time feedback data from the pressure system, temperature system, and flow rate system. The pressure system includes a valve, a stepping motor, and a pressure sensor located inside the quartz tube of the CVD apparatus. The pressure sensor is used to collect pressure values ​​in real time so that the control system can adjust the valve opening of the extraction piping in real time based on the pressure value inside the quartz tube to reach a target pressure. The valve is connected to the vacuum piping, and the stepping motor is used to drive the valve to open and close in constant step angles. When the control system adjusts the valve opening of the extraction piping in real time, it employs a periodic discontinuous angle control algorithm or a continuous angle control algorithm to automatically control the pressure based on the relationship between the pressure value and a preset pressure threshold. The control system adjusts the valve opening of the extraction piping in real time based on the pressure value to reach the target pressure. Based on the empirical angle-pressure curve, which is a curve showing how the pressure inside a quartz tube changes with valve opening under conditions where flow rate and temperature are constant, the valve is adjusted to the empirically experienced opening for the target pressure. This includes comparing the pressure value with a preset pressure threshold, and if the pressure value is greater than or equal to the pressure threshold, employing a periodic discontinuous angle control algorithm to automatically control the pressure; otherwise, employing a continuous angle control algorithm to automatically control the pressure. In the logic of the aforementioned periodic discontinuous angle control algorithm, Pressure sampling period ΔT and pressure change rate threshold ΔP θ The pressure change rate threshold ΔP is set. θ This is determined based on an empirical angle-velocity curve, which is a curve showing how the rate of pressure change inside a quartz tube changes with the opening of a butterfly valve, under conditions where the flow rate and temperature are constant. S1: Obtain the rate of pressure change ΔP within the pressure sampling period ΔT. S2: The absolute value of the pressure change rate ΔP is set to the pressure change rate threshold ΔP. θ Determine whether it exceeds, S2.1: The absolute value of the pressure change rate ΔP is set to the pressure change rate threshold ΔP. θ If it exceeds a certain value, the step angle and direction of the valve are determined based on the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold, and the positive or negative value of the pressure change rate ΔP. S2.2: The absolute value of the pressure change rate ΔP is set to the pressure change rate threshold ΔP. θ If it does not exceed the target pressure, the current pressure P is further measured, the relationship between the current pressure P and the target pressure and the sign of the pressure change rate ΔP are determined, and the step angle and direction of the valve are then determined. S3: Read the pressure after adjusting the valve opening, calculate the difference from the target pressure, determine if the difference is within the error range, maintain the current valve opening if the difference is within the error range, and continue sampling the pressure change rate within the next cycle and repeat the above process if the difference is not within the error range. An automated chemical vapor deposition (QV) deposition system capable of achieving atomic precision manufacturing, characterized by the following features.

2. The temperature system includes a temperature sensor, which is provided on the outer wall of a quartz tube corresponding to the location of the deposited sample and is used to obtain the temperature of the deposited sample location in real time. The control system adjusts the heating power and heating time based on the real-time temperature feedback from the temperature sensor to bring the temperature inside the quartz tube to a target temperature. An automated chemical vapor deposition (QV) deposition system capable of achieving atomic precision manufacturing as described in feature 1.

3. The in situ characterization system further includes an absorption spectrum detection device and a spectral shift / optical path calibration device, wherein the spectral detection device includes a light source, a light emitter, a light receiver, and a spectrometer connected to the light receiver, the spectral shift / optical path calibration device includes two moving rails, the light emitter and light receiver are each mounted on the two moving rails, and the tubular CVD apparatus includes a furnace body, a quartz tube, and a quartz boat for placing a sediment sample inside the quartz tube, the furnace body has two symmetrical light-passing slots parallel to the quartz tube, the two light-passing slots are, By using the axial centerline of the quartz tube as the axis of symmetry, and positioning the two movement rails of the spectral movement and optical path calibration device on the outside of the furnace body to correspond to two light-passing slots, the light-emitting device and light-receiving device can move linearly along the axial direction of the quartz tube, enabling in-situ detection of a sample at any position within the quartz tube. Light emitted from the light-emitting device passes through the light-passing slots, penetrates the quartz tube and the deposited sample inside it, and reaches the light-receiving device. Furthermore, spectral analysis is performed by a spectrometer based on the received light source, enabling in-situ detection of the deposited sample. An automated chemical vapor deposition (QV) deposition system capable of realizing atomic precision manufacturing as described in feature 2.

4. Further includes furnace body movement rails to enable the movement of the furnace body. An automated chemical vapor deposition (QV) deposition system capable of realizing atomic precision manufacturing as described in feature 3.

5. The flow system includes a flow meter, and the control system controls the flow meter based on set flow parameters to achieve the effect of flow control. An automated chemical vapor deposition (QV) deposition system capable of realizing atomic precision manufacturing as described in feature 4.

6. Includes touchscreen An automated chemical vapor deposition (QV) deposition system capable of realizing atomic precision manufacturing as described in feature 5.

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