Valve control method, controller and vaporization device insensitive to temperature fluctuations

Abstract

The present invention relates to the field of valve control, and specifically to a valve control method, controller and vaporization device that are insensitive to temperature fluctuations. The valve is arranged on the liquid inlet flow path of the vaporization part, and the method includes: receiving the current flow signal fed back by the flow sensor of the liquid inlet flow path; taking the derivative of the current flow signal and gaining it to obtain the current derivative compensation signal; performing PID control based on the flow setting value and the flow measurement value corresponding to the current flow signal to obtain the current valve control basic signal; estimating the current temperature control disturbance signal caused by the temperature fluctuation of the heating vaporization chamber based on the current flow signal and the valve control signal at the previous moment; superimposing the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain the current valve control signal. The present invention adopts a multi-level control strategy combining PID control, derivative compensation and disturbance compensation to control the valve to cope with the periodic disturbance of the heating system, which can ensure the stability and control accuracy of the liquid flow.

Description

Technical Field

[0001] The invention relates to the field of valve control, and in particular to a valve control method, a controller and a vaporization device which are insensitive to temperature fluctuations. Background Art

[0002] In the semiconductor manufacturing process, some processes involve vaporizing specific chemical liquids in a vacuum chamber and then introducing the vaporized gas into the reaction chamber through airflow to form a thin film, etch materials or perform other process treatments. The liquid vaporization process has a key impact on the uniformity and stability of the process reaction, because the process quality directly depends on the precise composition and flow of the gas in the reaction chamber. Especially in the chips with increasing manufacturing precision, any slight flow fluctuation may affect the thickness, uniformity and electrical properties of the film. Therefore, the semiconductor industry has extremely high requirements for the accuracy and response speed of the vaporization flow control system.

[0003] The current liquid vaporization flow control system usually includes a liquid flow path, a gas flow path, a heating vaporization chamber and a controller. The liquid flow path and the gas flow are respectively connected to the heating vaporization chamber. The heating vaporization chamber is responsible for mixing the liquid and gas and vaporizing them by heating. A liquid flow sensor and a valve are provided on the liquid flow path. The controller uses PID control on the valve according to the current flow signal fed back by the liquid flow sensor.

[0004] However, the inventor of this patent found that the heating process of the heated vaporization chamber is usually achieved by controlling the on and off of the 220V power supply by a relay to maintain the heated vaporization chamber at a fixed operating temperature. However, the heating method controlled by the relay will cause large fluctuations in the heating power during frequent switching processes. The fluctuation of the heating power will cause the cavity air pressure of the fixed volume in the heated vaporization chamber to fluctuate, thereby causing periodic fluctuations in the liquid flow rate. This fluctuation is manifested as a sinusoidal disturbance superimposed on the liquid flow rate, which increases the flow volatility and affects the stability and process accuracy of the gas flow after vaporization. This flow disturbance caused by the temperature control system is extremely unfavorable to semiconductor manufacturing. For example, in processes such as thin film deposition and ion etching, slight fluctuations in the flow rate will affect the uniformity of the film thickness, thereby affecting the performance and yield of the device. In addition, with the continuous improvement of semiconductor manufacturing processes, process tolerances are getting smaller and smaller, and more stringent requirements are placed on the stability of gas components. However, when dealing with such high-frequency and periodic disturbances, traditional PID control is difficult to effectively suppress the sinusoidal fluctuations caused by the temperature control system.

[0005] Therefore, it is urgent to solve the above problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a valve control method that is insensitive to temperature fluctuations. It adopts a multi-level control strategy combining PID control, derivative compensation and disturbance compensation to control the valve to cope with the periodic disturbance of the heating system, thereby ensuring the stability and control accuracy of the liquid flow.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: a valve control method that is insensitive to temperature fluctuations, the valve is arranged on the liquid inlet flow path of the vaporization part, and the method comprises:

[0008] Receiving a current flow rate signal fed back by a flow rate sensor of the liquid inlet flow path;

[0009] Derivative and gain the current flow signal to obtain a current derivative compensation signal;

[0010] Perform PID control based on the flow setting value and the flow measurement value corresponding to the current flow signal to obtain the current valve control basic signal;

[0011] estimating a current temperature control disturbance signal caused by temperature fluctuation of the vaporization part based on the current flow signal and the valve control signal at a previous moment;

[0012] Superimposing the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain a current valve control signal;

[0013] The valve is controlled using the current valve control signal.

[0014] In order to further eliminate the phase delay caused by the hysteresis of the flow sensor and improve the real-time performance of the disturbance compensation, the method also includes:

[0015] Performing phase compensation on the current flow signal; wherein,

[0016] In the calculation process of the current derivative compensation signal, the current valve control basic signal and the current temperature control disturbance signal, the current flow rate signals used are all current flow rate signals after phase compensation.

[0017] Furthermore, the transfer function of the current flow signal after compensation relative to the current flow signal before compensation is:

[0018] ,

[0019] Where, T z and T p They represent the zero and pole of the phase compensation transfer function, y 1 Represents the current flow signal after phase compensation, y 0 Indicates the current flow signal before compensation.

[0020] Furthermore, the calculation formula of the current temperature control disturbance signal is:

[0021] ,

[0022] In the formula, Indicates the current temperature control disturbance signal, Represents the transfer function of the liquid flow control system The inverse model of represents the filter, Indicates the current flow signal. Indicates the valve control signal at the previous moment.

[0023] Further, the calculation formula of the current derivative compensation signal is:

[0024] ,

[0025] In the formula, Indicates the current flow signal. Represents the gain factor.

[0026] The present invention also relates to a valve controller which is insensitive to temperature fluctuations. The valve is arranged on a liquid inlet flow path of a vaporizing part. The controller comprises:

[0027] A flow receiving unit, used to receive a current flow signal fed back by a flow sensor of the liquid inlet flow path;

[0028] A derivative compensation unit, used for taking the derivative of the current flow signal and performing gain calculation to obtain a current derivative compensation signal;

[0029] A PID controller, used to perform PID control based on a flow set value and a flow measurement value corresponding to the current flow signal to obtain a current valve control basic signal;

[0030] A disturbance observer, used for estimating a current temperature control disturbance signal caused by temperature fluctuation of the vaporization part based on the current flow signal and the valve control signal at a previous moment;

[0031] A superposition unit, used for superimposing the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain a current valve control signal;

[0032] A control unit is used to control the valve using the current valve control signal.

[0033] In order to further eliminate the phase delay caused by the hysteresis of the flow sensor and improve the real-time performance of disturbance compensation, the valve controller that is insensitive to temperature fluctuations also includes a phase compensation unit for performing phase compensation on the current flow signal; wherein,

[0034] In the calculation process of the current derivative compensation signal, the current valve control basic signal and the current temperature control disturbance signal, the current flow rate signals used are all current flow rate signals after phase compensation.

[0035] The present invention also relates to a vaporization device that is insensitive to temperature fluctuations, the vaporization device comprising a vaporization part and a controller, the vaporization part comprising a heated vaporization chamber and a liquid inlet flow path, the liquid inlet flow path communicating with the heated vaporization chamber and being provided with a valve and a flow sensor; wherein,

[0036] The controller is configured to control the valve using a valve control method that is insensitive to temperature fluctuations;

[0037] Or the controller is a valve controller that is insensitive to temperature fluctuations.

[0038] In order to enable the liquid to achieve a better vaporization state in the heated vaporization chamber, the vaporization portion further includes a carrier gas flow path connected to the heated vaporization chamber, and the carrier gas flow path is configured with a gas mass flow controller.

[0039] In order to facilitate the supply of liquid and carrier gas to the heated vaporization chamber, the vaporization device also includes a liquid source and a carrier gas source, the liquid source is connected to the liquid inlet flow path to supply liquid to the liquid inlet flow path, and the carrier gas source is connected to the carrier gas flow path to supply carrier gas to the carrier gas flow path.

[0040] After adopting the above technical solution, the present invention has the following beneficial effects:

[0041] 1. Effectively suppress flow fluctuations caused by temperature control disturbances: The vaporization part of the vaporization system uses a relay to control the on and off of the 220V power supply for heating, resulting in sinusoidal fluctuations in the heating process. This disturbance will directly affect the liquid flow and cause instability in the system flow. The present invention introduces disturbance observation, monitors and estimates temperature control disturbances in real time, and feeds them back to the control system as compensation signals, thereby significantly reducing the impact of temperature control fluctuations on the flow and keeping the flow stable;

[0042] 2. Improve the response speed to flow changes: The present invention adds derivative compensation on the basis of PID control, which can predict the change trend of flow in advance, so as to respond more quickly to sudden changes in flow. Derivative compensation enables the control system to perform feedforward compensation for instantaneous changes in flow, so even in the face of large disturbances, the system can quickly adjust and reduce deviations. This design is particularly suitable for semiconductor application scenarios with high requirements for flow accuracy, and effectively improves the response speed of the system;

[0043] In summary, the multi-level control strategy of the present invention has efficient anti-interference ability and fast response speed, realizes high-precision control of liquid vaporization flow in complex disturbance environment, and greatly improves the control quality and reliability of the system in applications such as semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a flow chart of a valve control method insensitive to temperature fluctuations of the present invention;

[0045] Figure 2 It is a principle block diagram of the valve controller which is insensitive to temperature fluctuations of the present invention;

[0046] Figure 3 It is a schematic structural diagram of a vaporization device insensitive to temperature fluctuations of the present invention;

[0047] Figure 4 It is a comparison diagram of the liquid flow curves of the present invention and the original solution;

[0048] Figure 5 for Figure 4 A partial enlarged view of

[0049] Figure 6 It is a comparison diagram of liquid flow curves in the frequency domain between the present invention and the original solution;

[0050] Figure 7 for Figure 6 A partial enlarged view of

[0051] In the figure, 1. valve; 2. heating vaporization chamber; 3. liquid inlet flow path; 4. flow sensor; 5. controller; 51. flow receiving part; 52. derivative compensation part; 53. PID controller; 54. disturbance observer; 55. superposition part; 56. control part; 57. phase compensation part; 6. carrier gas flow path; 7. liquid source; 8. carrier gas source; 9. gas mass flow controller. DETAILED DESCRIPTION

[0052] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0053] Embodiment 1: Figure 1 As shown, a valve control method that is insensitive to temperature fluctuations, the valve 1 is arranged on the liquid inlet flow path 3 of the vaporization part, and the method includes:

[0054] Step S1, receiving a current flow signal fed back by a flow sensor 4 of a liquid inlet flow path 3;

[0055] Step S2, performing phase compensation on the current flow signal;

[0056] Step S3, taking the derivative of the current flow signal and performing gain calculation to obtain the current derivative compensation signal; performing PID control based on the flow setting value and the flow measurement value corresponding to the current flow signal to obtain the current valve control basic signal; estimating the current temperature control disturbance signal caused by the temperature fluctuation of the vaporization part based on the current flow signal and the valve control signal at the previous moment;

[0057] Step S4, superimposing the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain the current valve control signal;

[0058] Step S5, controlling valve 1 using the current valve control signal.

[0059] Specifically, this embodiment introduces a derivative term of the flow rate into the control algorithm. By performing real-time calculation of the derivative of the current flow rate signal, it is possible to predict the change trend of the flow rate, thereby performing predictive compensation from the perspective of the flow rate results. It also introduces disturbance observation, and by continuously adjusting the compensation amount, the control method's ability to suppress flow disturbances is significantly improved. At the same time, a phase compensation scheme is used to eliminate the influence of the lag of the flow sensor 4 on the control system compensation.

[0060] In this embodiment, the flow sensor 4 is specifically a liquid mass flow sensor, which is used to measure the mass flow of the liquid in real time to ensure accurate feedback of the control system on the flow. The valve 1 is arranged on the liquid inlet flow path 3, and the liquid flow is controlled by controlling the opening of the valve 1. The valve 1 can be an electromagnetic brake composed of an electromagnetic coil or a piezoelectric brake composed of a piezoelectric ceramic material. The valve control signal is an electrical signal, which is transmitted to the electromagnetic / piezoelectric brake as an opening control signal, so as to achieve accurate adjustment of the opening of the valve 1 to meet the requirements of the fluid flow.

[0061] Among them, the specific calculation process of the current valve control signal is as follows:

[0062] The transfer function of the current flow signal after compensation relative to the current flow signal before compensation can be:

[0063] ,

[0064] Where, T z and T p They represent the zero and pole of the phase compensation transfer function, y 1 Represents the current flow signal after phase compensation, y 0 Indicates the current flow signal before compensation. Phase compensation can be achieved when Tz>Tp. For temperature flow sensors, the empirical values ​​are Tz=1 and Tp=0.6.

[0065] The calculation formula of the current valve control basic signal is:

[0066] ,

[0067] In the formula, and Respectively represent the basic valve control signals at the current moment and the previous moment; , , The control deviation signals respectively represent the current moment, the previous moment and the previous two moments, which are obtained based on the flow setting value and the flow measurement value at the corresponding moment; , and Represents the three coefficients of PID control.

[0068] The principle block diagram of the disturbance observer 54 is as follows: Figure 2 As shown in the figure, the transfer function of the output liquid flow to the input disturbance (referring to the change in liquid flow due to temperature control changes, where disturbance refers to the factors affecting the liquid flow) is:

[0069] ,

[0070] In the formula, represents the transfer function of the liquid flow control system, Represents the inverse model of the system transfer function. Because the inverse model is a non-causal system, a filter needs to be added , It can be a conventional first-order low-pass filter.

[0071] Further deduction shows that the transfer function of output flow to input disturbance is:

[0072] ,

[0073] In the formula, The transfer function representing the output flow rate subject to the input temperature control disturbance.

[0074] Depend on Figure 2 The observed disturbance can be derived as:

[0075] .

[0076] The calculation formula of the current derivative compensation signal can be:

[0077] ,

[0078] In the formula, Indicates the current flow signal. Represents the gain coefficient. The value of the gain coefficient is the full-scale flow rate divided by the corresponding voltage range.

[0079] In summary, the current valve control signal U is expressed as:

[0080] ,

[0081] In the formula, represents the inverse model of the system, , is the system time constant, Indicates the system gain Represents a filter, and a conventional first-order low-pass filter can be used. Represents the valve control signal at the previous moment, and the initial valve control signal is 0.

[0082] The current valve control signal U controls valve 1. Compared with the original PID control of valve 1, the liquid flow curve comparison is as follows Figure 4-Figure 7 As shown, the flow stability and accuracy are greatly improved.

[0083] Embodiment 2: Figure 2 As shown, a valve controller that is insensitive to temperature fluctuations, the valve 1 is arranged on the liquid inlet flow path 3 of the vaporization part, and the controller 5 includes:

[0084] The flow receiving unit 51 is used to receive the current flow signal fed back by the flow sensor 4 of the liquid inlet flow path 3;

[0085] The derivative compensation unit 52 is used to derive the current flow signal and gain it to obtain a current derivative compensation signal;

[0086] The PID controller 53 is used to perform PID control based on the flow setting value and the flow measurement value corresponding to the current flow signal to obtain the current valve control basic signal;

[0087] A disturbance observer 54, for estimating a current temperature control disturbance signal caused by temperature fluctuation of the vaporization part based on a current flow signal and a valve control signal at a previous moment;

[0088] A superposition unit 55, used for superimposing a current valve control basic signal, a current derivative compensation signal and a current temperature control disturbance signal to obtain a current valve control signal;

[0089] The control unit 56 is used to control the valve 1 using the current valve control signal.

[0090] Specifically, this embodiment introduces a disturbance observer 54 to monitor and estimate the temperature control disturbance in real time, and feeds it back to the control system as a compensation signal, which can effectively suppress the flow fluctuation caused by the temperature control disturbance, thereby significantly reducing the impact of the temperature control fluctuation on the flow, and keeping the flow stable. This embodiment also adds derivative compensation on the basis of the PID controller 53, which can predict the change trend of the flow in advance, so as to respond more quickly to sudden changes in the flow. Derivative compensation enables the control system to perform feedforward compensation for instantaneous changes in the flow, so even in the face of large disturbances, the system can quickly adjust and reduce deviations, thereby improving the system's response speed to flow changes.

[0091] Preferably, if Figure 2 As shown, the valve controller that is insensitive to temperature fluctuations also includes a phase compensation unit 57 for performing phase compensation on the current flow signal; wherein,

[0092] In the calculation process of the current derivative compensation signal, the current valve control basic signal and the current temperature control disturbance signal, the current flow signals used are all current flow signals after phase compensation.

[0093] Specifically, the phase compensation unit 57 calculates the phase offset of the response lag of the flow sensor 4 in the system according to the dynamic characteristics of the flow sensor 4. By introducing an appropriate phase advance amount into the control signal, it is ensured that the compensation signal is consistent with the flow change phase.

[0094] In this way, the phase delay caused by the hysteresis of the flow sensor 4 can be eliminated, and the real-time performance of disturbance compensation can be improved: the flow sensor 4 has a certain response lag when measuring the flow, resulting in a phase delay between the control system signal and the actual flow. This embodiment uses a phase compensation strategy to compensate the phase advance of the hysteresis response to the control signal, thereby offsetting the hysteresis effect of the flow sensor 4. This method ensures the real-time performance of the system feedback, keeps the control signal synchronized with the flow change, and significantly improves the control accuracy and stability of the system.

[0095] Embodiment 3: Figure 3 As shown, a vaporization device that is insensitive to temperature fluctuations includes a vaporization part and a controller 5. The vaporization part includes a heated vaporization chamber 2 and a liquid inlet flow path 3. The liquid inlet flow path 3 is connected to the heated vaporization chamber 2 and is equipped with a valve 1 and a flow sensor 4.

[0096] The controller 5 is configured to control the valve 1 using the valve control method insensitive to temperature fluctuations described in the first embodiment;

[0097] Or the controller 5 is the valve controller insensitive to temperature fluctuations as described in the second embodiment.

[0098] In this embodiment, if Figure 3As shown, preferably, the vaporization part further includes a carrier gas flow path 6 connected to the heating vaporization chamber 2 , and the carrier gas flow path 6 is provided with a gas mass flow controller 9 .

[0099] In this embodiment, if Figure 3 As shown, preferably, the vaporization device that is insensitive to temperature fluctuations also includes a liquid source 7 and a carrier gas source 8, the liquid source 7 is connected to the liquid inlet flow path 3 to supply liquid to the liquid inlet flow path 3, and the carrier gas source 8 is connected to the carrier gas flow path 6 to supply carrier gas to the carrier gas flow path 6.

[0100] The liquid source 7 is loaded with liquids such as TEOS and IPA; the carrier gas source 8 is loaded with liquids such as N 2 , Ar and other gases. The gas mass flow controller 9 is used to measure and control the carrier gas flow rate. During the vaporization process, the liquid and gas are mixed, so the control of the gas flow rate is crucial to maintaining the vaporization effect and flow stability. The heated vaporization chamber 2 heats the mixture of liquid and gas to about 140°C through the temperature control system, vaporizing the liquid and directing it to the external vacuum chamber. The temperature control system controls the heating of the vaporization chamber 2 at about 140°C by controlling the on and off of the 220V power supply through a relay, resulting in a certain volatility in the heating curve, which causes periodic disturbances to the flow rate.

[0101] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A valve control method that is insensitive to temperature fluctuations, wherein the valve (1) is arranged on a liquid inlet flow path (3) of a vaporization part, and is characterized in that: Methods include: Receiving a current flow signal fed back by a flow sensor (4) of the liquid inlet flow path (3); Derivative and gain the current flow signal to obtain a current derivative compensation signal; Perform PID control based on the flow setting value and the flow measurement value corresponding to the current flow signal to obtain the current valve control basic signal; estimating a current temperature control disturbance signal caused by temperature fluctuation of the vaporization part based on the current flow signal and the valve control signal at a previous moment; Superimposing the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain a current valve control signal; The valve (1) is controlled using the current valve control signal.

2. The temperature-fluctuation-insensitive valve control method according to claim 1, characterized in that: The method also includes: Performing phase compensation on the current flow signal; wherein, In the calculation process of the current derivative compensation signal, the current valve control basic signal and the current temperature control disturbance signal, the current flow rate signals used are all current flow rate signals after phase compensation.

3. The temperature-fluctuation-insensitive valve control method according to claim 2, characterized in that: The transfer function of the current flow signal after compensation relative to the current flow signal before compensation is: ， Where, T z and T p They respectively represent the zero point and pole of the transfer function of phase compensation, y1 represents the current flow signal after phase compensation, and y0 represents the current flow signal before compensation.

4. The temperature-fluctuation-insensitive valve control method according to claim 1, characterized in that: The calculation formula of the current temperature control disturbance signal is: ， In the formula, Indicates the current temperature control disturbance signal, Represents the transfer function of the liquid flow control system The inverse model of represents the filter, Indicates the current flow signal. Indicates the valve control signal at the previous moment.

5. The temperature-fluctuation-insensitive valve control method according to claim 1, characterized in that: The calculation formula of the current derivative compensation signal is: ， In the formula, Indicates the current flow signal. Represents the gain factor.

6. A valve controller insensitive to temperature fluctuations, the valve (1) being arranged on a liquid inlet flow path (3) of a vaporizing section, characterized in that: The controller (5) comprises: A flow receiving unit (51) for receiving a current flow signal fed back by a flow sensor (4) of the liquid inlet flow path (3); A derivative compensation unit (52) is used to derive the current flow signal and perform gain to obtain a current derivative compensation signal; A PID controller (53) is used to perform PID control based on a flow setting value and a flow measurement value corresponding to the current flow signal to obtain a current valve control basic signal; A disturbance observer (54) is used to estimate a current temperature control disturbance signal caused by temperature fluctuation of the vaporization part based on the current flow signal and the valve control signal at a previous moment; A superposition unit (55) is used to superimpose the current valve control basic signal, the current derivative compensation signal and the current temperature control disturbance signal to obtain a current valve control signal; A control unit (56) is used to control the valve (1) using the current valve control signal.

7. The temperature-fluctuation-insensitive valve controller according to claim 6, characterized in that: It also includes a phase compensation unit (57) for performing phase compensation on the current flow signal; wherein, In the calculation process of the current derivative compensation signal, the current valve control basic signal and the current temperature control disturbance signal, the current flow rate signals used are all current flow rate signals after phase compensation.

8. A vaporization device insensitive to temperature fluctuations, characterized in that: It comprises a vaporization part and a controller (5), the vaporization part comprising a heating vaporization chamber (2) and a liquid inlet flow path (3), the liquid inlet flow path (3) being connected to the heating vaporization chamber (2) and being provided with a valve (1) and a flow sensor (4); wherein: The controller (5) is configured to control the valve (1) by adopting the valve control method insensitive to temperature fluctuations according to any one of claims 1 to 5; Or the controller (5) is a valve controller that is insensitive to temperature fluctuations as described in claim 6 or 7.

9. The vaporization device insensitive to temperature fluctuations according to claim 8, characterized in that The vaporization section further comprises a carrier gas flow path (6) connected to the heating vaporization chamber (2), and the carrier gas flow path (6) is provided with a gas mass flow controller (9).

10. The vaporization device insensitive to temperature fluctuations according to claim 9, characterized in that It also includes a liquid source (7) and a carrier gas source (8), wherein the liquid source (7) is connected to the liquid inlet flow path (3) to supply liquid to the liquid inlet flow path (3), and the carrier gas source (8) is connected to the carrier gas flow path (6) to supply carrier gas to the carrier gas flow path (6).

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