Chemical vapor deposition automation device capable of realizing atomic-precision manufacturing

Abstract

The present invention belongs to the technical field of atomic layer deposition. Disclosed is a chemical vapor deposition automation device capable of realizing atomic-precision manufacturing. The device integrates a pressure system, a temperature system and a flow system, thereby realizing full-process automated control over a chemical vapor deposition process; in terms of pressure control, a valve experience opening angle is introduced, such that a target pressure can be quickly approached, thereby greatly shortening a response time; and a discontinuous angle control algorithm is further designed, such that relatively high control precision can also be achieved for large-pressure control during the chemical vapor deposition process. Moreover, the device is also provided with an in-situ characterization system, such that the real-time detection of a deposition condition of a sample during the chemical deposition process is realized by means of a corresponding apparatus. Furthermore, in the present application, a furnace moving track is provided, such that a furnace can be moved to thoroughly expose a heating area to the air during a cooling phase after a production process has been completed, thereby achieving the maximum cooling efficiency and improving the overall production efficiency.

Description

A chemical vapor deposition automation equipment that can achieve atomic precision manufacturing Technical Field

[0001] The present invention relates to chemical vapor deposition automation equipment capable of realizing atomic precision manufacturing, and belongs to the technical field of atomic layer deposition. Background Art

[0002] With the continuous development of modern scientific research, the precision of processing technology and manufacturing technology has been continuously improved. The discipline of mechanical engineering has begun to continuously integrate and intersect with disciplines such as chemistry, physics, and materials, giving birth to a new frontier field of "atomic scale and near-atomic scale manufacturing."

[0003] The so-called atomic scale and near-atomic scale manufacturing refers to the process of manufacturing and processing at the atomic and near-atomic scales. Atomic layer deposition technology ALD is a method of using atomic layer deposition technology to grow thin films layer by layer on the surface of materials. It can achieve very precise film thickness control and material composition regulation, and is widely used in microelectronics, optoelectronics, touch screens and other fields.

[0004] In order to achieve precise control of the deposited samples, the corresponding CVD equipment needs to have accurate temperature, pressure, and flow control systems. However, most domestic CVD equipment is currently assembled from instruments and components from different manufacturers. The parameters of each system require manual adjustment and intervention, and the degree of automation is low. Moreover, since the control accuracy depends on manual labor, the control accuracy is low and cannot meet the requirements of atomic layer deposition.

[0005] Summary of the Invention

[0006] In order to solve the current problems, the present invention provides a chemical vapor deposition automation equipment that can achieve atomic precision manufacturing, the equipment including a pressure system, a temperature system, a flow system and a control system; wherein the pressure system, temperature system and flow system are all connected to the control system; the control system realizes fully automatic control of the equipment based on the real-time feedback data of the pressure system, temperature system and flow system.

[0007] Optionally, the pressure system includes a valve, a stepper motor and a pressure sensor arranged in a quartz tube of the CVD equipment, the pressure sensor is used to collect the pressure value in the quartz tube in real time, so that the control system can adjust the valve opening of the exhaust pipeline in real time according to the pressure value to achieve the target pressure, which is the pressure value required at each stage of the thin film deposition process; the valve is connected to the vacuum pipeline, and the stepper motor is used to drive the valve to open or close at a certain step angle. Under the premise of a certain gas flow rate, controlling the valve opening of the vacuum pipeline can directly control the pressure; when the control system adjusts the valve opening of the exhaust pipeline in real time, it uses a periodic discontinuous angle control algorithm or a continuous angle control algorithm to automatically control the pressure according to the relationship between the pressure value and a pre-set pressure threshold.

[0008] Optionally, the control system adjusts the valve opening of the exhaust pipeline in real time according to the pressure value to achieve the target pressure, including:

[0009] The valve is adjusted to the empirical opening angle of the target pressure according to the angle-pressure empirical curve; the angle-pressure empirical curve is a curve showing the change of the pressure in the quartz tube with the valve opening angle under fixed flow and temperature conditions.

[0010] The method for obtaining the angle-pressure experience curve includes: maintaining a certain temperature and measuring the change in pressure as the opening angle of the butterfly valve changes under a certain gas flow rate.

[0011] The method for obtaining the angle-rate empirical curve includes: maintaining a certain temperature and a certain gas flow, setting a sampling period, and measuring the change in the pressure change rate as the butterfly valve opening angle changes during the sampling period.

[0012] According to the angle-pressure empirical curve, the butterfly valve opening angle corresponding to the target pressure required at each stage of the thin film deposition process is determined, which is the empirical opening angle. Rapidly opening the butterfly valve to the empirical opening angle can make the actual pressure value quickly reach near the target pressure value.

[0013] Compare the pressure value with the preset pressure threshold. When the pressure value is greater than or equal to the pressure threshold, use the periodic discontinuous angle control algorithm to perform automatic pressure control. Otherwise, use the continuous angle control algorithm to perform automatic pressure control.

[0014] In the actual deposition process, when the pressure reaches a certain value P θ When the pressure is increased to a certain value, the time required is much longer than the time required to reduce the same pressure value. θ It is recorded as the pressure threshold, and different control algorithms are used for pressure values ​​greater than and less than the pressure threshold.

[0015] Optionally, the periodic discontinuous angle control algorithm logic is:

[0016] Set the pressure sampling period ΔT and the pressure change rate threshold ΔP θ The pressure change rate threshold ΔP θ Determined according to the angle-rate empirical curve; the angle-rate empirical curve is a curve showing the pressure change rate in the quartz tube as the butterfly valve opening angle changes under fixed flow and temperature conditions; according to the changing trend of the angle-rate empirical curve, it can be seen that as the butterfly valve opening angle changes, the pressure change rate gradually increases to a certain value and then decreases, that is, there is a maximum value for the pressure change rate.

[0017] S1, obtain the pressure change rate ΔP within the pressure sampling period ΔT;

[0018] S2: Determine whether the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ ;

[0019] S2.1, if the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ , then the valve step angle and direction are further determined based on the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold, as well as the positive or negative value of the pressure change rate ΔP;

[0020] There are multiple levels according to the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold, such as:

[0021] 1) When the absolute value of the pressure change rate ΔP exceeds ΔP max When ΔP is positive, the butterfly valve steps forward at a step angle of α1.

[0022] 2) When the absolute value of the pressure change rate ΔP exceeds ΔP max When ΔP is positive, the butterfly valve steps forward at a step angle of α2.

[0023] 3) When the absolute value of the pressure change rate ΔP exceeds ΔP max When ΔP is positive, the butterfly valve steps forward at a step angle of α3.

[0024] The above step angles satisfy α1<α2<α3.

[0025] In the above three cases, if the pressure change rate ΔP is a negative value, the butterfly valve steps in the opposite direction at the corresponding step angle; wherein, the butterfly valve is opened when it steps in the forward direction, and is closed when it steps in the reverse direction.

[0026] S2.2, if the absolute value of the pressure change rate ΔP does not exceed the set pressure change rate threshold ΔP θ , then further collect the current pressure value P, and judge the magnitude of the current pressure value P and the target pressure as well as the positive or negative pressure change rate ΔP, and then determine the step angle and direction of the valve:

[0027] 1) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is positive, the current angle of the butterfly valve is maintained or the valve is stepped in the opposite direction at a step angle α4;

[0028] 2) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is negative, step in the opposite direction at a step angle α5;

[0029] 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is positive, then step forward at a step angle α4;

[0030] 4) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is negative, the current angle of the butterfly valve is maintained or the step angle α5 is stepped forward.

[0031] Among them, α4<α5, and α4<<<α1, α5<<<α1.

[0032] S3, reads the pressure after adjusting the valve opening angle, calculates the difference with the target pressure, and determines whether the difference is within the error range. If the difference is within the error range, maintain the current valve opening angle; if the difference is not within the error range, continue to sample the pressure change rate in the next cycle and repeat the above process.

[0033] Optionally, the temperature system includes a temperature sensor, which is arranged on the outer wall of the quartz tube at the corresponding deposition sample position, and is used to obtain the temperature at the deposition sample position in real time; the control system adjusts the heating power and heating time according to the real-time temperature feedback from the temperature sensor so that the temperature inside the quartz tube reaches the target temperature value.

[0034] Optionally, the equipment further comprises an in-situ characterization system, which comprises an absorption spectrum detection device and a spectrum shift and optical path calibration device; the absorption spectrum detection device is used to realize online in-situ characterization of the deposited sample;

[0035] The spectrum detection device includes a light source, a light source emitting device, a light source receiving device and a spectrometer connected to the light source receiving device;

[0036] The spectrum movement and optical path calibration device includes two moving rails, on which the light source emitting device and the light source receiving device are respectively installed; the light source emitting device and the light source receiving device are moved by the moving rails, thereby realizing online in-situ characterization of samples at any position in the quartz tube.

[0037] The tubular CVD equipment includes a furnace, a quartz tube and a quartz boat in the quartz tube for carrying deposited samples; in order to enable the light emitted by the light source emitting device to pass through the furnace, and in order to realize online in-situ characterization of samples at any position in the quartz tube, two symmetrical light-through grooves parallel to the quartz tube are opened on the furnace of the present application, and the width of the light-through grooves is set to enable the light emitted by the light source emitting device and the light received by the light source receiving device to pass through completely; the two light-through grooves are symmetrical with the axial center line of the quartz tube, and the two moving tracks in the spectrum movement and optical path calibration device are respectively located at the positions corresponding to the two light-through grooves on the outside of the furnace, so that the light source emitting device and the light source receiving device can move in a straight line along the axial direction of the quartz tube to realize in-situ detection of samples at any position in the quartz tube; the light emitted by the light source emitting device passes through the light-through groove, the quartz tube and the deposited sample therein to reach the light source receiving device, and then the spectrometer performs spectral analysis based on the received light source to realize in-situ detection of the deposited sample.

[0038] Optionally, the spectrum movement and optical path calibration device also includes four stepper motors and is equipped with a four-axis optical path automatic calibration system. The four stepper motors are respectively recorded as a first transverse stepper motor, a first longitudinal stepper motor, a second transverse stepper motor and a second longitudinal stepper motor; wherein, the first transverse stepper motor and the first longitudinal stepper motor realize the positioning of the light source emitting device in the horizontal plane through a band-pass ball screw and a movable rail, and the second transverse stepper motor and the second longitudinal stepper motor are used to control the rotation of the light source emitting device in the horizontal plane and the vertical plane.

[0039] Optionally, the four-axis optical path automatic calibration system uses a single-chip microcomputer or PLC controller to control the stepper motors. By setting the PWM wave of each motor, its speed can be controlled. By comparing the returned light intensity, the optical path can be fine-tuned to maximize the received light intensity, facilitating subsequent spectral analysis.

[0040] Optionally, the light source is a white light source with a continuous spectrum and a wavelength covering at least 200-1050nm, wherein the luminous flux in the ultraviolet band with a wavelength in the range of 250nm-400nm is greater than 10mW / mm 2 ·sr·nm; and the light source has strong collimation, and the light spot can be focused into a circle with a diameter of 1mm within a distance of 0.5m.

[0041] Optionally, the equipment also includes a furnace moving track for realizing the movement of the furnace. After the deposition is completed, the furnace can be moved so that the quartz tube heating area is completely exposed to the air, thereby maximizing the heat dissipation efficiency and improving the overall production efficiency.

[0042] Optionally, the flow system includes a flow meter, and the control system controls the flow meter according to set flow parameters to achieve a flow control effect.

[0043] Optionally, the equipment further includes a touch screen, and the technician sets corresponding parameters through the touch screen.

[0044] The beneficial effects of the present invention are:

[0045] By providing a CVD device that integrates a pressure system, a temperature system, and a flow system, full automated control of the chemical vapor deposition process is achieved. Specifically, in terms of pressure control, the introduction of a valve opening angle based on experience can quickly approach the target pressure and greatly improve the response time. A discontinuous angle control algorithm is further designed to achieve high control accuracy for high pressure control in the chemical vapor deposition process. In terms of temperature control, a PID control algorithm is used to control the on and off of the solid-state relay to achieve a temperature control effect. Furthermore, the equipment is also equipped with an in-situ characterization system, which realizes real-time detection of sample deposition during the chemical deposition process through corresponding devices. In addition, combined with the changes in system temperature and pressure, it is possible to further obtain the law of sample or reaction system changes with temperature, pressure and other environmental conditions, thereby determining the optimal deposition conditions. Furthermore, the present application provides a furnace moving track, which can move the furnace to completely expose the heating area to the air when the production process is completed and waiting for heat dissipation, thereby maximizing heat dissipation efficiency and improving overall production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] FIG1 is a schematic diagram of the relationship between the furnace moving track and the furnace position in a CVD device provided by an embodiment of the present invention, wherein 1 is the furnace, 2 is the quartz tube, and 12 is the furnace moving track.

[0048] FIG2 is a flow chart of a method for automatically controlling pressure in a control system provided by an embodiment of the present invention.

[0049] FIG3 is an empirical angle-pressure curve corresponding to a gas flow rate of 0 at room temperature of 25° C.

[0050] FIG4 is an empirical angle-velocity curve corresponding to a gas flow rate of 0 at room temperature of 25° C.

[0051] Figure 5 is a schematic diagram of the in-situ characterization system in the CVD equipment provided by an embodiment of the present invention; wherein, 1, furnace, 2, quartz tube, 3, quartz boat, 4, deposited sample, 5, light-through slot, 6, light source, 7, light source emitting device, 8, light source receiving device, 9, spectrometer, 10, track, 11, stepping motor.

[0052] Figure 6 is a three-dimensional schematic diagram of a four-axis optical path calibration system of an in-situ characterization system in a CVD device provided by an embodiment of the present invention; wherein 1101 is a first transverse stepping motor, 1102 is a first longitudinal stepping motor, 1103 is a second longitudinal stepping motor, and 1104 is a second transverse stepping motor. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] Example 1:

[0055] The present embodiment provides a chemical vapor deposition automation equipment that can achieve atomic precision manufacturing, including a pressure system, a temperature system, a flow system and a control system; wherein the pressure system, the temperature system and the flow system are all connected to the control system; the control system realizes full automatic control of the equipment according to the real-time feedback data of the pressure system, the temperature system and the flow system. The equipment is provided with a display touch screen, and the technician can directly set the corresponding deposition parameters, and the control system can complete the entire deposition process according to the set parameters. In addition, in order to cool down as quickly as possible after the deposition is completed, the present application designs a furnace moving track 12, as shown in Figure 1. While waiting for heat dissipation, the furnace is moved to completely expose the heating area of ​​the quartz tube 2 to the air, thereby maximizing the heat dissipation efficiency and improving the overall production efficiency.

[0056] The following is an introduction to each part in turn:

[0057] (1) The pressure system includes a valve, a stepper motor and a pressure sensor installed in a quartz tube of the CVD equipment. The pressure sensor is used to collect the pressure value in the quartz tube in real time so that the control system can adjust the valve opening of the exhaust pipeline in real time according to the pressure value to achieve the target pressure; the valve is connected to the vacuum pipeline, and the stepper motor is used to drive the valve to open or close at a certain step angle; when the control system adjusts the valve opening of the exhaust pipeline in real time, it uses a periodic discontinuous angle control algorithm or a continuous angle control algorithm to automatically control the pressure according to the relationship between the pressure value and the pre-set pressure threshold. The specific control process can be referred to Figure 2. Algorithm 1 in Figure 2 is the periodic discontinuous angle control algorithm, and Algorithm 2 is the continuous angle control algorithm.

[0058] When the control system adjusts the valve opening degree of the exhaust line in real time, it first adjusts the valve opening angle to the target pressure based on the empirical angle-pressure curve. The empirical angle-pressure curve shows how the pressure inside the quartz tube changes with the valve opening angle under fixed flow and temperature conditions. The empirical angle-pressure curves can be pre-obtained for different temperature and flow conditions. During the deposition process, simply obtaining the current gas flow and temperature will determine the valve opening angle corresponding to the target pressure, which is the empirical angle. Figure 3 shows the empirical angle-pressure curve for a gas flow of 0 at room temperature (25°C).

[0059] Considering that the pressure in the quartz tube varies greatly during the actual deposition process, it can change from vacuum to atmospheric pressure. When the pressure reaches a certain value P θ When the pressure is greater than P, the time required to increase the pressure to a certain value is much longer than the time required to reduce the same pressure value. θ The pressure should be different from that less than P θ Therefore, the pressure threshold value P is preset in this application. θ (The pressure threshold P can be determined by technicians. θ The value of, for example, P θ =20kPa), according to the current pressure value and the pre-set pressure threshold P θ The size relationship adopts periodic discontinuous angle control algorithm or continuous angle control algorithm to automatically control the pressure, specifically:

[0060] When the pressure value is greater than or equal to the pressure threshold, a periodic discontinuous angle control algorithm is used for automatic pressure control, otherwise a continuous angle control algorithm is used for automatic pressure control. Among them, the continuous angle control algorithm is the PID control algorithm, which is a relatively mature control algorithm in the industrial field. Please refer to the introduction in the patent CN112695297A, a method for controlling chamber pressure in a semiconductor process, or the introduction in the patent CN116931610A, a method and device for rapid response of pressure control, which will not be elaborated here. The logic of the periodic discontinuous angle control algorithm is as follows:

[0061] Set the pressure sampling period ΔT and the pressure change rate threshold ΔP θ The pressure change rate threshold ΔP θ Determined by the angle-rate empirical curve; the angle-rate empirical curve is the curve of the pressure change rate in the quartz tube as the valve opening angle changes under fixed flow and temperature conditions; according to the actual angle-rate empirical curve, as the valve opening angle increases, the pressure change rate has a maximum value ΔP max , so the pressure change rate threshold ΔP θ Can be set to ΔP θ =K*ΔP max , K = 0.5 ~ 0.8, the specific value is determined by the technicians, Figure 4 is the angle-rate empirical curve corresponding to the gas flow rate of 0 at room temperature 25 ° C, it can be seen that the maximum pressure change rate ΔP when the gas flow rate is 0 at 25 ° C max =0.38kPa / s.

[0062] S1, obtain the pressure change rate ΔP within the pressure sampling period ΔT;

[0063] S2: Determine whether the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ ;

[0064] S2.1, if the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ , the valve step angle and direction are further determined according to the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold, as well as the positive and negative values ​​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 levels, for example:

[0065] 1) When the absolute value of the pressure change rate ΔP exceeds ΔP max When ΔP is positive, the butterfly valve steps forward at a step angle of α1.

[0066] 2) When the absolute value of the pressure change rate ΔP exceeds ΔPmax When ΔP is positive, the butterfly valve steps forward at a step angle of α2.

[0067] 3) When the absolute value of the pressure change rate ΔP exceeds ΔP max When ΔP is positive, the butterfly valve steps forward at a step angle of α3.

[0068] The above step angles satisfy α1<α2<α3.

[0069] In the above three cases, if the pressure change rate ΔP is a negative value, the butterfly valve steps in the opposite direction at the corresponding step angle; wherein, the butterfly valve is opened when it steps in the forward direction, and is closed when it steps in the reverse direction.

[0070] In one implementation, α1 = 0.05°, α2 = 0.1°, and α3 = 0.15°.

[0071] S2.2, if the absolute value of the pressure change rate ΔP does not exceed the set pressure change rate threshold ΔP θ , then further collect the current pressure value P, and judge the magnitude of the current pressure value P and the target pressure as well as the positive or negative pressure change rate ΔP, and then determine the step angle and direction of the valve. Specifically:

[0072] 1) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is positive, the current angle of the butterfly valve is maintained or the valve is stepped in the opposite direction at a step angle α4;

[0073] 2) If the current pressure value P is less than the target pressure and the pressure change rate ΔP is negative, step in the opposite direction at a step angle α5;

[0074] 3) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is positive, then step forward at a step angle α4;

[0075] 4) If the current pressure value P is greater than the target pressure and the pressure change rate ΔP is negative, the current angle of the butterfly valve is maintained or the step angle α5 is stepped forward.

[0076] Among them, α4<α5, and α4<<<α1, α5<<<α1.

[0077] In one implementation, α4 ​​= 0.001°, α5 = 0.002°

[0078] S3, read the pressure in the quartz tube after the above adjustment, and calculate the difference with the target pressure to determine whether the difference is within the error range. If the difference is within the error range, maintain the current valve opening angle; if the difference is not within the error range, continue to sample the pressure change rate in the next cycle and repeat the above process.

[0079] (2) The temperature system includes a temperature sensor, which is arranged on the outer wall of the quartz tube at the corresponding deposition sample position and is used to obtain the temperature at the deposition sample position in real time; the control system adjusts the heating power and heating time according to the real-time temperature feedback from the temperature sensor so that the temperature inside the quartz tube reaches the target temperature value.

[0080] (3) The flow system includes a flow meter, and the control system controls the flow meter according to the set flow parameters to achieve the flow control effect.

[0081] (4) In order to realize real-time monitoring of the chemical vapor deposition process for atomic-level material manufacturing, the equipment provided in the embodiment of the present application is also provided with an in-situ characterization system, which includes an absorption spectrum detection device and a spectrum movement and light path calibration device; as shown in FIG5 , the absorption spectrum detection device includes a light source 6, a light source emitting device 7, a light source receiving device 8, and a spectrometer 9 connected to the light source receiving device 8; the spectrum movement and light path calibration device includes two moving rails 10 and corresponding stepper motors 11, and the light source emitting device 7 and the light source receiving device 8 are respectively installed on the two moving rails 10; the tubular CVD equipment includes a furnace 1, a quartz tube 2 and A quartz boat 3 is placed inside the quartz tube 2 to carry the deposited sample. Two symmetrical light-through slots 5 parallel to the quartz tube are provided on the furnace 1, and the two light-through slots 5 take the axial center line of the quartz tube as the axis of symmetry. Two movable tracks 10 in the spectrum moving device are located at positions corresponding to the two light-through slots 5 on the outside of the furnace 1, so that the light source emitting device 7 and the light source receiving device 8 can move in a straight line along the axial direction of the quartz tube 2. The light emitted by the light source emitting device 7 passes through the light-through slots 5, the quartz tube 2 and the deposited sample 4 therein to reach the light source receiving device 8, and then the spectrometer 9 performs spectral analysis based on the received light source to realize in-situ detection of the deposited sample 4.

[0082] The length of the light-passing slot 5 can be determined according to actual conditions, and the width is set so as to allow the light emitted by the light source emitting device 7 and the light received by the light source receiving device 8 to pass through completely.

[0083] In order to ensure that the light emitted by the light source emitting device 7 can be accurately received by the light source receiving device 8, the present application has designed a four-axis optical path calibration system, which realizes the optical path alignment between the light source emitting device 7 and the light source receiving device 8 through four stepper motors 11; as shown in Figure 6, the first horizontal stepper motor 1101 and the first vertical stepper motor 1102 are used for coarse adjustment, and the second horizontal stepper motor 1104 and the second vertical stepper motor 1103 are used for fine adjustment. The first horizontal stepper motor 1101 and the first vertical stepper motor 1102 are positioned in the horizontal plane through a bandpass ball screw and a slide rail, and the second horizontal stepper motor 1104 and the second vertical stepper motor 1103 are used to control the rotation of the light source emitting device 7 in the horizontal plane and the vertical plane. The combination of the four motors can realize the calibration of the light source. The control of the four stepper motors is realized by an STM32 single-chip microcomputer, and the rotation speed can be controlled by setting the PWM wave of each motor. By comparing the returned light intensity, the optical path can be fine-tuned to maximize the received light intensity, which is convenient for subsequent spectral analysis.

[0084] Light source 6 meets the following conditions:

[0085] 1) Continuous spectrum, wavelength covering 200-2000nm;

[0086] 2) The overall light intensity is strong enough, especially in the ultraviolet band (200nm-400nm), the luminous flux is greater than 10mW / mm 2 ·sr·nm;

[0087] 3) Strong collimation, the light spot can be focused into a circle with a diameter of 1mm within a distance of 0.5m.

[0088] Considering the high temperature environment of the deposition process, the red furnace will have a certain impact on the light source signal. Therefore, there will be certain errors in the analysis based on the spectral signal directly. This application also obtains the temperature gradient compensation spectrum in advance, and then performs the corresponding compensation on the obtained spectrum before analysis, so as to obtain more accurate analysis results. Specifically:

[0089] In step 1, no sample is placed, so that the light path passes through the quartz tube and the quartz boat to reach the light source receiving device 8, i.e., the spectrometer detector, and a spectrum is obtained, which is recorded as the initial spectrum.

[0090] Step 2: gradually increase the temperature to 900°C, and take a spectrum every ΔT starting from 100°C, and subtract it from the initial spectrum to obtain the red light compensation spectrum under different temperature gradients. The specific value of ΔT can be determined by the technician according to the actual situation, such as ΔT = 10°C or ΔT = 25°C.

[0091] Subsequently, a more accurate absorption spectrum can be obtained as the final spectrum by subtracting the corresponding red light compensation spectrum from the spectrum at a certain temperature obtained in real time during the deposition process.

[0092] When analyzing a substance based on absorption spectrum, the absorbance calculation formula is as follows:

[0093] Absorbance = log (incident light intensity / transmitted light intensity)

[0094] The incident light intensity is the intensity of the light emitted by the light source emitting device 7 , and the transmitted light intensity is the intensity of the light received by the light source receiving device 8 .

[0095] for example:

[0096] Before placing the sample, light passes through the quartz boat and quartz tube. At room temperature (25°C), there is no red light. The intensity of the transmitted light at this time is recorded as L1.

[0097] After placing the sample, in the experimental environment, light passes through the quartz tube, quartz boat, and sample at a temperature of 800°C and with red light. The intensity of the transmitted light at this time is recorded as L2. Let the light intensity of the red light compensation spectrum corresponding to 800°C be recorded as L3. Then the absorbance (measured value) without compensation is A=lg(L1 / L2), and the actual value (true value) A'=lg(L1 / (L2-L3)). Therefore, the compensation value of the red light compensation spectrum corresponding to 800°C is Δ 800 =A'-A=lg(L2 / (L2-L3)).

[0098] The above method is used to obtain the compensation values ​​Δ1, Δ2, Δ3, ..., ΔT of the red light compensation spectrum corresponding to each ΔT degree Celsius starting from 100°C. n .

[0099] In the subsequent deposition process, if the deposition temperature is set to 800°C, the obtained spectrum needs to be subtracted from the compensation value Δ corresponding to the red light compensation spectrum at 800°C. 800 , and then analyze based on the final spectrum.

[0100] Step 3: Analyze the deposition status of the deposition process based on the final spectrum.

[0101] Since the light source emitting device 7 and the light source receiving device 8 of the present application are respectively installed on two movable rails 10, and the axial length of the light-passing groove opened on the furnace can enable the light source to reach any position in the quartz tube 2, the sample at any position in the quartz tube 2 can be detected in real time during the deposition process by moving the light source emitting device 7 and the light source receiving device 8 to obtain the sample deposition situation.

[0102] Existing in-situ techniques all focus on in-situ characterization of a single point. This application achieves movable in-situ characterization within a quartz tube by synchronously moving the white light source's light emitting device 7 and light receiving device 8. This innovation has significant implications for exploring the growth window of new materials.

[0103] In many CVD processes, after determining the temperature, pressure, carrier gas flow rate and other conditions, the material will grow at certain determined positions, which are usually called growth windows. In conventional experimental processes, it is necessary to conduct experiments repeatedly at different positions and perform offline characterization after the experiment. It may take several or even dozens of experiments to roughly determine its growth window. The process is cumbersome and takes a lot of time. The system and method of the present application can be moved arbitrarily during the experiment, and the growth window can be judged by characterizing the growth of materials at different positions, which makes it possible to quickly obtain better deposition effects.

[0104] This application provides a CVD device that integrates a pressure system, a temperature system, and a flow system, achieving fully automated control of the chemical vapor deposition process. Specifically, in pressure control, the introduction of a valve opening angle based on experience allows for rapid approach to the target pressure, significantly improving response time. Furthermore, a discontinuous angle control algorithm has been designed to achieve high control accuracy for high pressure control during the chemical vapor deposition process. In temperature control, a PID control algorithm is used to control the on and off of a solid-state relay to achieve temperature control. Furthermore, the equipment is equipped with an in-situ characterization system that enables real-time detection of sample deposition during the chemical deposition process through corresponding devices. Furthermore, by combining changes in system temperature and pressure, it is possible to further understand how the sample or reaction system changes with environmental factors such as temperature and pressure, thereby determining the optimal deposition conditions. Furthermore, this application provides a furnace movement track that can be used to move the furnace after the production process is completed and waiting for heat dissipation, completely exposing the heating zone to the air, maximizing heat dissipation efficiency and improving overall production efficiency.

[0105] Some steps in the embodiments of the present invention may be implemented using software, and the corresponding software program may be stored in a readable storage medium, such as a CD or a hard disk.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A chemical vapor deposition automation equipment capable of achieving atomic precision manufacturing, characterized in that: The equipment includes a pressure system, a temperature system, a flow system and a control system; wherein the pressure system, the temperature system and the flow system are all connected to the control system; the control system realizes fully automatic control of the equipment based on real-time feedback data of the pressure system, the temperature system and the flow system; The pressure system includes a valve, a stepper motor, and a pressure sensor disposed within a quartz tube of the CVD device. The pressure sensor is used to collect the pressure value within the quartz tube in real time, so that the control system adjusts the valve opening of the exhaust pipeline in real time according to the pressure value to achieve the target pressure. The valve is connected to the vacuum pipeline, and the stepper motor is used to drive the valve to open or close at a certain step angle. When the control system adjusts the valve opening of the exhaust pipeline in real time, it uses 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 exhaust pipeline in real time according to the pressure value to achieve the target pressure, including: Adjust the valve opening angle to the target pressure based on the angle-pressure empirical curve; the angle-pressure empirical curve is a curve showing the change of the pressure in the quartz tube with the valve opening angle under fixed flow and temperature conditions; Compare the pressure value with the pre-set pressure threshold. When the pressure value is greater than or equal to the pressure threshold, use the periodic discontinuous angle control algorithm to automatically control the pressure. Otherwise, use the continuous angle control algorithm to automatically control the pressure. The periodic discontinuous angle control algorithm logic is: Set the pressure sampling period ΔT and the pressure change rate threshold ΔP θ The pressure change rate threshold ΔP θ Determined according to the angle-rate empirical curve; the angle-rate empirical curve is a curve showing the rate of change of pressure in the quartz tube as a function of the opening angle of the butterfly valve under fixed flow and temperature conditions; 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, if the absolute value of the pressure change rate ΔP exceeds the set pressure change rate threshold ΔP θ , then the valve step angle and direction are further determined based on the degree to which the absolute value of the pressure change rate exceeds the set pressure change rate threshold, as well as the positive or negative value of the pressure change rate ΔP; S2.2, if the absolute value of the pressure change rate ΔP does not exceed the set pressure change rate threshold ΔP θ , then further collect the current pressure value P, and judge the magnitude of the current pressure value P and the target pressure as well as the positive or negative pressure change rate ΔP, and then determine the step angle and direction of the valve; S3, reads the pressure after adjusting the valve opening angle, calculates the difference with the target pressure, and determines whether the difference is within the error range. If the difference is within the error range, maintain the current valve opening angle; if the difference is not within the error range, continue to sample the pressure change rate in the next cycle and repeat the above process.

2. The equipment according to claim 1, characterized in that The temperature system includes a temperature sensor, which is arranged on the outer wall of the quartz tube at the corresponding deposition sample position and is used to obtain the temperature at the deposition sample position in real time; the control system adjusts the heating power and heating time according to the real-time temperature feedback from the temperature sensor so that the temperature inside the quartz tube reaches the target temperature value.

3. The equipment according to claim 2, characterized in that The equipment also includes an in-situ characterization system, which includes an absorption spectrum detection device and a spectrum shifting and optical path calibration device. The spectrum detection device includes a light source, a light source emitting device, a light source receiving device, and a spectrometer connected to the light source receiving device. The spectrum shifting and optical path calibration device includes two movable rails, with the light source emitting device and the light source receiving device respectively mounted on the two movable rails. The tubular CVD apparatus includes a furnace, a quartz tube, and a quartz boat inside the quartz tube for carrying a deposited sample. The furnace is provided with two symmetrical light passage slots parallel to the quartz tube, with the two light passage slots being symmetrical about the axial centerline of the quartz tube. The two movable rails in the spectrum shifting and optical path calibration device are respectively located outside the furnace at positions corresponding to the two light passage slots, thereby enabling the light source emitting device and the light source receiving device to move linearly along the axial direction of the quartz tube to achieve in-situ detection of a sample at any position within the quartz tube. Light emitted by the light source emitting device passes through the light passage slots, the quartz tube, and the deposited sample therein to reach the light source receiving device, whereupon the spectrometer performs spectral analysis based on the received light source to achieve in-situ detection of the deposited sample.

4. The equipment according to claim 3, characterized in that The equipment also includes a furnace moving track for realizing the movement of the furnace.

5. The equipment according to claim 4, characterized in that The flow system includes a flow meter, and the control system controls the flow meter according to set flow parameters to achieve a flow control effect.

6. The device according to claim 5, characterized in that The device also includes a touch screen.

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