Automated chemical vapor deposition equipment that enables 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] The present invention relates to an automated chemical vapor deposition facility capable of achieving atomic precision manufacturing, and belongs to the technical field of atomic layer deposition. [Background technology]

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

[0003] Atomic and near-atomic scale manufacturing refers to manufacturing and processing processes at the atomic and near-atomic scale. Atomic layer deposition (ALD) is a technique for growing films layer by layer on the surface of a material using atomic layer deposition technology. Because it allows for precise control of film thickness and material composition, it is widely used in fields such as microelectronics, optoelectronics, and touchscreens. Summary of the Invention [Problem to be solved by the invention]

[0004] To achieve precise control of deposition samples, the corresponding CVD equipment must be equipped with high-precision temperature, pressure, and flow control systems. However, most CVD equipment currently used in China is composed of instruments and components from different manufacturers, and each system parameter must be manually adjusted and intervened, resulting in low automation. Furthermore, control accuracy is also reduced due to manual labor, 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 equipment capable of atomic precision manufacturing, which includes a pressure system, a temperature system, a flow rate system, and a control system, wherein the pressure system, the temperature system, and the flow rate system are all connected to a control system, and the control system realizes fully automatic control of the equipment based on real-time feedback data from the pressure system, the temperature system, and the flow rate system.

[0006] Preferably, the pressure system includes a valve, a stepping motor, and a pressure sensor installed in 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 bleed pipe in real time based on the pressure value in the quartz tube to reach the 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 at a constant step angle. The pressure can be directly controlled by controlling the valve opening of the vacuum pipe, assuming a constant gas flow rate. When adjusting the valve opening of the bleed pipe in real time, the control system automatically controls the pressure using 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.

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

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

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

[0010] Based on the empirical curve of angle vs. pressure, the empirical opening of the butterfly valve corresponding to the target pressure required at each stage of the film deposition process is determined. By quickly opening the butterfly valve to the empirical opening, the actual pressure value can quickly approach the target pressure value.

[0011] The pressure value is compared with a preset pressure threshold value, and if the pressure value is equal to or greater than the pressure threshold value, a periodic non-continuous angle control algorithm is adopted to automatically control the pressure; otherwise, a continuous angle control algorithm is adopted to automatically control the pressure.

[0012] In a real deposition process, the pressure is a certain value P θ Once this is reached, the time required to increase the pressure by a given value becomes much longer than the time required to decrease the pressure by the same value. θ is set as a pressure threshold, and different control algorithms are employed for pressure values ​​greater than and less than the pressure threshold.

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

[0014] S1: The pressure change rate ΔP within the pressure sampling period ΔT is acquired. S2: Pressure change rate threshold ΔP, where the absolute value of the pressure change rate ΔP is set θ Determine if it exceeds: S2.1: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP θ If the absolute value of the pressure change rate exceeds the set pressure change rate threshold, the valve step angle and direction 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. The degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold is divided into multiple stages. For example, 1) The absolute value of the pressure change rate ΔP is ΔP max If the value of ΔP exceeds 50% of the normal pressure and ΔP is a positive value, 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 difference exceeds 70% of the normal pressure and ΔP is a positive value, 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 difference exceeds 80% of the normal pressure and ΔP is a positive value, the butterfly valve is stepped in the positive direction by a step angle α3. The above step angles satisfy α1<α2<α3.

[0015] In the above three cases, when the pressure change rate ΔP is negative, the butterfly valve is stepped in the reverse direction by a corresponding step angle, where a positive step of the butterfly valve indicates an opening operation and a reverse step indicates a closing operation.

[0016] S2.2: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP θ If it does not exceed the target pressure, the current pressure value P is further collected, and the magnitude relationship between the current pressure value P and the target pressure and the sign of the pressure change rate ΔP are determined, and the valve step angle and direction are further determined. 1) If the current pressure value P is smaller than the target pressure and the pressure change rate ΔP is a positive value, the butterfly valve is maintained at the current angle or is stepped in the reverse direction by a step angle α4. 2) If the current pressure value P is smaller than the target pressure and the pressure change rate ΔP is a negative value, a step is made in the reverse direction at a step angle α5. 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is a positive value, a step is made in the positive direction at a step angle α4. 4) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is a negative value, the butterfly valve is maintained at the current angle or is stepped in the positive direction by a step angle α5. Here, α4<α5, α4<<α1, and α5<<α1.

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

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

[0019] Preferably, the equipment further includes an in-situ characterization system including an absorption spectrum detection device and a spectrum shifting and optical path calibration device, and the absorption spectrum detection device realizes online in-situ characterization of the deposition 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, and the light-emitting device and the light-receiving device are mounted on the two moving rails respectively. The moving rails enable the movement of the light-emitting device and the light-receiving device, enabling online in-situ characterization of the sample at any position inside the quartz tube.

[0020] The tubular CVD apparatus includes a furnace body, a quartz tube, and a quartz boat for placing deposition samples inside the quartz tube. To allow light emitted from the light-emitting device to pass through the furnace body and to realize online in-situ characterization of samples located at any position inside the quartz tube, the furnace body of the present application has two symmetrical light-passing slots parallel to the quartz tube, with the widths of the light-passing slots set to allow the light emitted from the light-emitting device and the light received by the light-receiving device to pass completely through. The two light-passing slots share the axial centerline of the quartz tube as their axis of symmetry. Two moving rails of the spectral shifting / optical path calibration device are located outside the furnace body at positions corresponding to the two light-passing slots, allowing the light-emitting device and the light-receiving device to move linearly along the axial direction of the quartz tube, thereby enabling in-situ detection of samples located at any position inside the quartz tube. The light emitted from the light emitting device passes through the light passing slot, penetrates the quartz tube and the deposition sample inside it, and reaches the light receiving device, where a spectrometer performs spectral analysis based on the received light source, thereby realizing in situ detection of the deposition sample.

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

[0022] Preferably, the four-axis optical path automatic calibration system uses a single-chip microcomputer or PLC controller to control the stepping motors, and the rotation speed of each motor can be controlled by setting the PWM waveform of each motor. By comparing the intensity of the returned light, the optical path can be fine-tuned to maximize the received light intensity for subsequent spectrum analysis.

[0023] Preferably, the light source is a white light source, the spectrum is continuous, and the wavelength range includes at least 200 to 1050 nm. In this case, in the ultraviolet band having a wavelength in the range of 250 nm to 400 nm, the luminous flux is more than 10 mW / mm 2 ·sr·nm, and the light source has strong collimation, allowing the spot to be focused into a circle with a diameter of 1 mm at a distance of less than 0.5 m.

[0024] Preferably, the equipment further includes a furnace body moving rail for moving the furnace body, which can completely expose the heated area of ​​the quartz tube to the air after deposition is completed, thereby 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 a flow control effect.

[0026] Preferably, the equipment further includes a touch screen, and the technician can set the corresponding parameters through the touch screen. [Effects of the Invention]

[0027] The beneficial effects of the present invention are as follows: By providing a CVD equipment integrating pressure, temperature, and flow systems, fully automated control of the chemical vapor deposition process is achieved. Specifically, in pressure control, the introduction of an empirical valve opening allows for rapid approach to the target pressure, significantly improving response time. Furthermore, by designing a non-continuous angle control algorithm, high control accuracy can be achieved even for large pressure control in the chemical vapor deposition process. In temperature control, a PID control algorithm is used to control the on / off of a solid-state relay, achieving temperature control effects. Furthermore, the equipment is equipped with an in-situ characterization system, which enables real-time detection of the sample deposition status during the chemical deposition process using corresponding devices. This, combined with changes in the system's temperature and pressure, allows for further understanding of how the sample or reaction system changes with environmental changes such as temperature and pressure, thereby enabling optimal deposition conditions to be determined. Furthermore, the present application is equipped with a furnace body moving rail, which allows the furnace body to be moved during the heat dissipation stage after the production process is completed, completely exposing the heated area to air, maximizing heat dissipation efficiency, and improving overall production efficiency. [Brief explanation of the drawings]

[0028] In order to more clearly explain the technical solutions in the embodiments of the present invention, the following briefly introduces 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 derive other drawings based on these drawings without any creative work. [Figure 1] 1 is a schematic diagram showing the positional relationship between a furnace body moving rail and a furnace body in a CVD apparatus according to one embodiment of the present invention, in which reference numeral 1 denotes the furnace body, reference numeral 2 denotes a quartz tube, and reference numeral 12 denotes a furnace body moving rail. [Figure 2] 4 is a flowchart of a method for automatically controlling pressure using a control system according to one embodiment of the present invention. [Figure 3] This is a diagram of the empirical curve of angle vs. pressure corresponding to the case where the gas flow rate is 0 at room temperature of 25°C. [Figure 4] This is a diagram of the empirical curve of angle vs. velocity corresponding to the case where the gas flow rate is 0 at room temperature of 25°C. [Figure 5] FIG. 1 is a schematic diagram of an in-situ characterization system for a CVD apparatus according to one embodiment of the present invention, in which reference numeral 1 denotes a furnace body, reference numeral 2 denotes a quartz tube, reference numeral 3 denotes a quartz boat, reference numeral 4 denotes a deposition sample, reference numeral 5 denotes a light passage slot, reference numeral 6 denotes a light source, reference numeral 7 denotes a light emitting device, reference numeral 8 denotes a light receiving device, reference numeral 9 denotes a spectrometer, reference numeral 10 denotes a rail, and reference numeral 11 denotes a stepping motor. [Figure 6] FIG. 11 is a schematic three-dimensional diagram of a four-axis optical path calibration system of an in-situ characteristic evaluation system in a CVD apparatus according to one embodiment of the present invention, in which reference numeral 1101 denotes a first horizontal stepping motor, reference numeral 1102 denotes a first vertical stepping motor, reference numeral 1103 denotes a second vertical stepping motor, and reference numeral 1104 denotes a second horizontal stepping motor. DETAILED DESCRIPTION OF THE INVENTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following describes in more detail the embodiments of the present invention with reference to the drawings.

[0030] Example 1 This embodiment provides an automated chemical vapor deposition (CVD) equipment capable of atomic precision manufacturing, including a pressure system, a temperature system, a flow rate system, and a control system. The pressure system, temperature system, and flow rate system are all connected to a control system, which realizes fully automatic 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 touchscreen display, allowing technicians to directly set corresponding deposition parameters, and the control system completes the entire deposition process based on the set parameters. To facilitate rapid cooling after deposition is completed, the present application also designs a furnace body moving rail 12. As shown in FIG. 1, this allows the furnace body to move during the heat dissipation phase, completely exposing the heated area of ​​the quartz tube 2 to air, maximizing heat dissipation efficiency and improving overall production efficiency.

[0031] Each part will be explained in turn below. (1) The pressure system includes a valve, a stepping motor, and a pressure sensor installed in the quartz tube of the CVD equipment. The pressure sensor collects pressure values ​​in real time so that the control system can adjust the valve opening of the bleed pipe in real time based on the pressure value in the quartz tube to reach the target pressure. The valve is connected to the vacuum pipe, and the stepping motor is used to drive the valve to open and close at a constant step angle. When adjusting the valve opening of the bleed pipe in real time, the control system automatically controls the pressure using a periodic discontinuous angle control algorithm or a continuous angle control algorithm based on the magnitude relationship between the pressure value and a preset pressure threshold. See Figure 2 for a specific control flow, where Algorithm 1 in Figure 2 is the periodic discontinuous angle control algorithm, and Algorithm 2 is the continuous angle control algorithm.

[0032] When adjusting the valve opening of the extraction pipe in real time, the control system first adjusts the valve to the empirical opening for the target pressure based on the empirical angle-pressure curve. The empirical angle-pressure curve is the curve showing how the pressure inside the quartz tube changes with the valve opening when the flow rate and temperature are constant. The empirical angle-pressure curves for different temperature and flow rate conditions can be obtained in advance. For a specific deposition process, the valve opening corresponding to the target pressure, i.e., the empirical opening, can be determined simply by obtaining the current gas flow rate and temperature. Figure 3 shows the empirical angle-pressure curve for a room temperature of 25°C and a gas flow rate of 0.

[0033] In an actual deposition process, the pressure inside the quartz tube can vary over a wide range, from vacuum to atmospheric pressure. θ Once this is reached, the time required to increase the pressure by a given value becomes much longer than the time required to decrease the pressure by the same value. θ For larger pressures, P θ It is necessary to adopt a different pressure control method for the case of a smaller pressure. Therefore, in this application, the pressure threshold P θ is preset (specifically, the pressure threshold P θ The value of P can be determined, for example θ = 20 kPa). The current pressure value and the preset pressure threshold P θ Based on the magnitude relationship between the pressure and the pressure, a periodic discontinuous angle control algorithm or a continuous angle control algorithm is adopted to automatically control the pressure. When the pressure value is equal to or greater than 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. The PID control algorithm, which is a continuous angle control algorithm, is a relatively mature control algorithm in the industrial field. See the introductions in Chinese Patent CN112695297A, "Method for controlling chamber pressure in semiconductor processing," or CN116931610A, "Fast-response method and apparatus for pressure control," and detailed descriptions are 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 is set, and the pressure change rate threshold ΔP θ is determined according to the empirical curve of angle vs. velocity. The empirical curve of angle vs. velocity is a curve showing how the rate of pressure change in the quartz tube changes with the valve opening under the condition that the flow rate and temperature are constant. From the actual empirical curve of angle vs. velocity, as the valve opening increases, the rate of pressure change reaches a maximum value ΔP max Therefore, the pressure change rate threshold ΔP θ is ΔP θ =K*ΔP max The K value can be set to 0.5~0.8, and the specific value is determined by the engineer. Figure 4 shows the empirical curve of the angle vs. velocity when the gas flow rate is 0 at room temperature of 25°C. When the gas flow rate is 0 at 25°C, the maximum value of the pressure change rate ΔP max =0.38kPa / s.

[0034] S1: The pressure change rate ΔP within the pressure sampling period ΔT is acquired. S2: Pressure change rate threshold ΔP, where the absolute value of the pressure change rate ΔP is set θ Determine whether it has been exceeded. S2.1: The absolute value of the pressure change rate ΔP is set as the pressure change rate threshold ΔP θIf the absolute value of the pressure change rate exceeds the set pressure change rate threshold, the valve step angle and direction 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. Specifically, the degree to which the absolute value of the pressure change rate exceeds the 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 of ΔP exceeds 50% of the normal pressure and ΔP is a positive value, 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 difference exceeds 70% of the normal pressure and ΔP is a positive value, 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 difference exceeds 80% of the normal pressure and ΔP is a positive value, 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 above three cases, when the pressure change rate ΔP is negative, the butterfly valve is stepped in the reverse direction by a corresponding step angle, where a positive step of the butterfly valve indicates an opening operation and a reverse step indicates a 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 it does not exceed the target pressure, the current pressure value P is further collected, and the magnitude relationship between the current pressure value P and the target pressure and the positive or negative sign of the pressure change rate ΔP are determined, and the valve step angle and direction are further determined. 1) If the current pressure value P is smaller than the target pressure and the pressure change rate ΔP is a positive value, the butterfly valve is maintained at the current angle or is stepped in the reverse direction by a step angle α4. 2) If the current pressure value P is smaller than the target pressure and the pressure change rate ΔP is a negative value, a step is made in the reverse direction at a step angle α5. 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is a positive value, a step is made in the positive direction at a step angle α4. 4) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is a negative value, the butterfly valve is maintained at the current angle or is stepped in the positive direction by a step angle α5. Here, α4<α5, α4<<α1, and α5<<α1.

[0038] In one embodiment, α4=0.001° and α5=0.002°. S3: The pressure inside the quartz tube after the above adjustment is read, the difference from the target pressure is calculated, and it is determined whether the difference is within the error range. If the difference is within the error range, the current valve opening is maintained. If the difference is not within the error range, sampling of the pressure change rate in the next period continues, and the above process is repeated.

[0039] (2) The temperature system includes a temperature sensor, which is provided on the outer wall of the quartz tube corresponding to the deposition sample position and is used to obtain the temperature of the deposition sample position in real time. The control system adjusts the heating power and heating time based on the real-time temperature feedback from the temperature sensor so that the temperature inside the quartz tube reaches a target temperature value.

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

[0041] (4) To achieve real-time monitoring of chemical vapor deposition processes for atomic-level material production, the equipment provided in the embodiments of this application further includes an in-situ characterization system including an absorption spectrum detection device and a spectral shift and optical path calibration device. As shown in FIG. 5, the absorption spectrum detection device includes a light source 6, a light-emitting device 7, a light-receiving device 8, and a spectrometer 9 connected to the light-receiving device 8. The spectral shift and optical path calibration device includes two moving rails 10 and corresponding stepping motors 11, and the light-emitting device 7 and the light-receiving device 8 are respectively attached to 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 in the quartz tube 2. The furnace body 1 is provided with two symmetrical light-passing slots 5 parallel to the quartz tube, with the two light-passing slots 5 sharing the axial centerline of the quartz tube as their axis of symmetry. Two moving rails 10 of the spectral moving device are located on the outside of the furnace body 1, respectively, at positions corresponding to the two light-passing slots 5, thereby allowing the light-emitting device 7 and the light-receiving device 8 to move linearly along the axial direction of the quartz tube 2. The light emitted from the light-emitting device 7 passes through the light-passing slots 5, penetrates the quartz tube 2 and the deposition sample 4 therein, and reaches the light-receiving device 8. The light is then spectrally analyzed by a spectrometer 9 based on the received light source, thereby achieving in-situ detection of the deposition sample 4.

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

[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 four stepping motors 11 are used to calibrate the optical path between the light-emitting device 7 and the light-receiving device 8. As shown in FIG. 6 , a first horizontal stepping motor 1101 and a first vertical stepping motor 1102 are used for coarse adjustment, and a second horizontal stepping motor 1104 and a second vertical stepping motor 1103 are used for fine adjustment. The first horizontal stepping motor 1101 and the first vertical stepping motor 1102 drive ball screws and slide rails to achieve positioning in the horizontal plane, and the second horizontal 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. Light source calibration can be achieved by simply combining four motors. The four stepping motors are controlled by an STM32 single-chip microcontroller, and their rotation speeds can be controlled by setting the PWM waveforms for each motor. By comparing the intensity of the returned light, the optical path can be fine-tuned to maximize the received light intensity and facilitate subsequent spectrum analysis.

[0044] The light source 6 satisfies the following conditions: 1) The spectrum is continuous, with a wavelength range of 200 to 2000 nm. 2) The overall light intensity is strong enough, especially in the ultraviolet range (200nm-400nm), with a luminous flux of >10mW / mm 2 ·sr·nm. 3) Collimation is strong, and the spot can be focused into a circle with a diameter of 1 mm within a distance of 0.5 m.

[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, so direct analysis based on the spectral signal will result in certain errors. In this application, the temperature gradient compensation spectrum is obtained in advance, and the obtained spectrum is then subjected to corresponding compensation before analysis, thereby obtaining more accurate analysis results. Specifically, In step 1, without leaving the sample, the light path passes through the quartz tube and the quartz boat and reaches the light receiving device 8, that is, the spectrometer detector, and one spectrum is obtained as an initial spectrum.

[0046] In step 2, the temperature is gradually increased to 900°C, and a spectrum is taken every ΔT from 100°C. The difference between the spectrum and 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, such as ΔT = 10°C or ΔT = 25°C.

[0047] The corresponding red-light compensation spectrum can then be subtracted from a spectrum acquired at a temperature in real time during the deposition process to obtain a more accurate absorption spectrum as the final spectrum.

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

[0049] For example, before the sample is placed in, the light passes through the quartz boat and the quartz tube, and at room temperature (25°C), there is no red light, and the transmitted light intensity at this time is defined as L1. After the sample is placed in the test environment, the light passes through the quartz tube, the quartz boat, and the sample. At a temperature of 800°C, red light is present. The transmitted light intensity at this time is L2, and the light intensity of the red light compensation spectrum corresponding to 800°C is L3. The absorbance (measured value) without compensation is A = lg(L1 / L2), and the actual value (true value) is A' = lg(L1 / (L2-L3)). Therefore, the compensation value Δ of the red light compensation spectrum corresponding to 800°C is 800 =A'-A=lg(L2 / (L2-L3)).

[0050] Using the above method, the compensation values ​​Δ1, Δ2, Δ3, ..., Δ of the red light compensation spectrum corresponding to every ΔT°C from 100°C are calculated. n get.

[0051] In the subsequent deposition process, when the deposition temperature is set to 800°C, the compensation value Δ 800 The final spectrum is obtained by subtracting the above, and further analysis should be performed based on the final spectrum.

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

[0053] In the present application, the light-emitting device 7 and the light-receiving device 8 are respectively attached to two movable rails 10, and the axial length of the light-passing slot opened in the furnace body allows the light source to reach any position inside the quartz tube 2. Therefore, during the deposition process, by moving the light-emitting device 7 and the light-receiving device 8, the sample at any position inside the quartz tube 2 can be detected in real time, and the deposition status of the sample can be obtained.

[0054] Existing in-situ techniques are all limited to in-situ characterization at a single point. In this application, we achieve mobile in-situ characterization within a quartz tube by synchronously moving a white light source emitter 7 and a light receiver 8. This innovation plays an important role in exploring the growth window of new materials.

[0055] In many CVD processes, once conditions such as temperature, pressure, and carrier gas flow rate are determined, material grows at a specific location. This location is commonly referred to as the "growth window." Conventional experimental processes require repeated experiments at different locations, followed by offline characterization. As a result, roughly determining the growth window can require several to dozens of experiments, which is a cumbersome and time-consuming process. The system and method disclosed herein allows for arbitrary movement during the experimental process, allowing the growth window to be determined by characterizing the growth of material at different locations, thereby enabling superior deposition results to be achieved quickly.

[0056] This application provides a CVD apparatus that integrates pressure, temperature, and flow systems, thereby achieving fully automated control of the chemical vapor deposition process. Specifically, in pressure control, the introduction of an empirical valve opening allows for rapid approach to the target pressure, significantly improving response time. Furthermore, a discontinuous angle control algorithm is designed to achieve high control accuracy even for large pressures in the chemical vapor deposition process. In temperature control, a PID control algorithm is used to control the on / off of a solid-state relay, achieving effective temperature control. Furthermore, the equipment is equipped with an in-situ characterization system, which enables real-time detection of the sample deposition status during the chemical deposition process. This, combined with changes in the system's temperature and pressure, allows for a better understanding of how the sample or reaction system changes with environmental changes such as temperature and pressure, thereby enabling the determination of optimal deposition conditions. Furthermore, this application is equipped with a furnace body moving rail, which allows the furnace body to be moved during the heat dissipation stage after the production process is completed, 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 realized by software, and the corresponding software program can be stored in a readable storage medium such as an optical disk or a hard disk.

[0058] The above description is merely a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the scope of the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automated chemical vapor deposition facility capable of achieving atomic precision manufacturing, comprising: a pressure system, a temperature system, a flow rate system, and a control system, wherein the pressure system, the temperature system, and the flow rate system are all connected to a control system, and the control system realizes fully automatic control of the equipment based on real-time feedback data from the pressure system, the temperature system, and the flow rate system; the pressure system includes a valve, a stepping motor, and a pressure sensor provided in a quartz tube of the CVD apparatus, the pressure sensor being used to collect pressure values ​​in real time so that the control system can adjust the valve opening of the bleed pipe in real time based on the pressure value in the quartz tube to reach a target pressure; the valve is connected to a vacuum pipe, and the stepping motor is used to drive the valve to open and close at a constant step angle; and when adjusting the valve opening of the bleed pipe in real time, the control system automatically controls the pressure by adopting a periodic discontinuous angle control algorithm or a continuous angle control algorithm based on the magnitude relationship between the pressure value and a preset pressure threshold; The control system adjusts the valve opening of the extraction pipe in real time based on the pressure value to reach the target pressure, adjusting the valve to an empirical opening degree of the target pressure based on an empirical curve of angle and pressure, which is a curve showing how the pressure in the quartz tube changes with the valve opening degree under conditions where the flow rate and temperature are constant; comparing the pressure value with a preset pressure threshold value; and if the pressure value is equal to or greater than the pressure threshold value, adopting a periodic non-continuous angle control algorithm to automatically control the pressure; otherwise, adopting a continuous angle control algorithm to automatically control the pressure; The logic of the periodic non-continuous angle control algorithm comprises: Pressure sampling period ΔT and pressure change rate threshold ΔP θ is set, and the pressure change rate threshold ΔP θ is determined based on the empirical curve of angle and velocity, which is the curve that shows how the pressure change rate in the quartz tube changes with the opening of the butterfly valve under conditions where the flow rate and temperature are constant, S1: Obtain the pressure change rate ΔP within the pressure sampling period ΔT, S2: Pressure change rate threshold ΔP, where the absolute value of the pressure change rate ΔP is set θ Determine whether it exceeds S2.1: Pressure change rate threshold ΔP, where the absolute value of the pressure change rate ΔP is set θ If the absolute value of the pressure change rate exceeds the set pressure change rate threshold, 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: Pressure change rate threshold ΔP, where the absolute value of the pressure change rate ΔP is set θ If the target pressure is not exceeded, the current pressure value P is further collected, and the magnitude relationship between the current pressure value P and the target pressure and the positive or negative sign of the pressure change rate ΔP are determined, and the valve step angle and direction are determined. S3: Read the pressure after adjusting the valve opening, calculate the difference from the target pressure, and determine whether the difference is within the error range. If the difference is within the error range, maintain the current valve opening. If the difference is not within the error range, continue sampling the pressure change rate in the next period and repeat the above process. An automated chemical vapor deposition facility capable of achieving atomic precision manufacturing.

2. the temperature system includes a temperature sensor, the temperature sensor being provided on an outer wall of the quartz tube corresponding to the deposition sample position, and being used to acquire the temperature of the deposition sample position in real time; The control system adjusts the heating power and heating time based on the real-time temperature feedback from the temperature sensor so that the temperature inside the quartz tube reaches the target temperature value.

2. The automated chemical vapor deposition facility capable of achieving atomic precision manufacturing according to claim 1.

3. The present invention further includes an in-situ characterization system including an absorption spectrum detection device and a spectrum shift / light path calibration device, wherein the spectrum detection device includes a light source, a light emitting device, a light receiving device, and a spectrometer connected to the light receiving device, the spectrum shift / light path calibration device includes two moving rails, and the light emitting device and the light receiving device are respectively attached to the two moving rails, and the tubular CVD apparatus includes a furnace body, a quartz tube, and a quartz boat for placing a deposition sample in the quartz tube, and the furnace body has two symmetrical light passing slots parallel to the quartz tube, and the two light passing slots are: The axial centerline of the quartz tube is the axis of symmetry, and the two moving rails of the spectrum movement and optical path calibration device are located at positions corresponding to the two light passage slots on the outside of the furnace body, respectively, so that the light emitting device and the light receiving device can move linearly along the axial direction of the quartz tube, realizing in-situ detection of a sample located at any position inside the quartz tube. The light emitted from the light emitting device passes through the light passage slots, penetrates the quartz tube and the deposited sample inside it, and reaches the light receiving device. Then, a spectrometer performs spectral analysis based on the received light source, realizing in-situ detection of the deposited sample.

3. The automated chemical vapor deposition equipment capable of achieving atomic precision manufacturing according to claim 2.

4. Further includes a furnace body moving rail for realizing the movement of the furnace body.

4. The automated chemical vapor deposition facility capable of achieving atomic precision manufacturing according to claim 3.

5. The flow system includes a flow meter, and the control system controls the flow meter based on a set flow parameter to achieve a flow control effect.

5. The automated chemical vapor deposition equipment capable of achieving atomic precision manufacturing according to claim 4.

6. Also includes a touchscreen 6. The automated chemical vapor deposition facility capable of achieving atomic precision manufacturing according to claim 5.

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