WO2020211440A1

WO2020211440A1 - Chamber pressure control method and apparatus, and semiconductor device

Info

Publication number: WO2020211440A1
Application number: PCT/CN2019/127864
Authority: WO
Inventors: 郑文宁; 赵迪; 陈正堂
Original assignee: 北京七星华创流量计有限公司
Priority date: 2019-04-18
Filing date: 2019-12-24
Publication date: 2020-10-22
Also published as: TW202040302A; JP2021524068A; CN111831022B; CN111831022A; TWI719807B; JP7041697B2

Abstract

A chamber pressure control method and apparatus, and a semiconductor device, capable of precisely and rapidly controlling the pressure inside a chamber to stabilise same within a preset range, thereby improving the processing quality and product yield. The method comprises the following steps: S1: detecting the actual pressure value inside a chamber; S2: calculating the difference between the actual pressure value and a preset target pressure value; determining whether the difference exceeds a preset range and, if so, then implementing step S3; and, if not, then the process finishes; S3: acquiring a control coefficient, the control coefficient being the product of a curvature and a preset PID coefficient, and the curvature being the curvature corresponding to a current position parameter value of an execution unit in a curve relating to pressure and position parameters corresponding to a current gas flow value; S4: on the basis of the difference and the control coefficient, calculating a position parameter adjustment amount of the execution unit and outputting same to the execution unit, and returning to step S2.

Description

Chamber pressure control method and device, and semiconductor equipment

Technical field

The invention relates to the technical field of semiconductor manufacturing, in particular to a chamber pressure control method and device, and semiconductor equipment.

Background technique

In the fields of semiconductor manufacturing and photovoltaics, the reaction chamber such as oxidation furnace is the most important equipment in the semiconductor process. In the process of coating and other processes, the reaction gas introduced into the reaction chamber includes H ₂ , HCl, a large amount of O ₂ , a small amount of C ₂ H ₂ Cl ₂ and N _2, etc. These reaction gases need to be under constant pressure conditions To ensure that the process results such as the thickness of the coating meet the requirements, the pressure in the reaction chamber should be kept stable at the set pressure. If the actual process pressure is greater or less than the set pressure, the thickness of the coating will be affected. Currently, there is an urgent need for a method and device that can accurately and quickly control the pressure in the reaction chamber.

Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a chamber pressure control method and device, and semiconductor equipment, which can accurately and quickly control the pressure in the chamber to stabilize it within a preset range , Which can improve process quality and yield.

To achieve the above objective, the present invention provides a chamber pressure control method, which includes the following steps:

S1, the actual pressure value inside the detection chamber;

S2: Calculate the difference between the actual pressure value and the preset target pressure value; and determine whether the difference exceeds the preset range, if it exceeds, proceed to step S3; if it does not exceed, then the process ends;

S3. Obtain a control coefficient, where the control coefficient is the product of the curvature and the preset PID coefficient, where the curvature is: in the curve of the pressure and the position parameter of the actuator corresponding to the current gas flow value, and The curvature corresponding to the current position parameter value of the execution unit;

S4: Calculate and obtain the position parameter adjustment amount of the execution unit based on the difference value and the control coefficient, and output it to the execution unit, and return to step S2.

Optionally, before the step S1, the method further includes:

S0, pre-store the sample data template;

Wherein, the sample data template includes different correspondences between the gas flow values and the curves, and different correspondences between the position parameter values and curvatures in each of the curves;

The step S3 further includes:

S31: Acquire the curvature from the sample data template according to the current gas flow value and the current position parameter value of the execution unit;

S32: Calculate the product of the curvature obtained from the sample data template and the PID coefficient.

Optionally, the execution unit includes a pressure regulating valve, and the position parameter of the execution unit is a valve position of the pressure regulating valve corresponding to its opening.

Optionally, the initial value of the position parameter of the execution unit is set within a range corresponding to the value range of the opening of the pressure regulating valve; the value range of the opening is 30°-50°.

Optionally, the value range of the gas flow value is 3-50 L/min.

Optionally, in the step S1, detecting the pressure of the chamber at the exhaust port as the actual pressure value;

Alternatively, the difference between the internal pressure of the chamber and the atmospheric pressure outside the chamber is detected as the actual pressure value.

As another technical solution, the present invention also provides a chamber pressure control device, including a detection unit, a control unit and an execution unit, wherein:

The detection unit is used to detect the actual pressure value inside the chamber and send it to the control unit;

The control unit is used to calculate the difference between the actual pressure value and a preset target pressure value; and determine whether the difference exceeds a preset range, and if it exceeds, obtain a control coefficient, and based on the difference sum The control coefficient is calculated to obtain the position parameter adjustment value of the execution unit, and output to the execution unit; the control coefficient is the product of the curvature and the preset PID coefficient, wherein the curvature is: corresponding to the current gas flow value In the curve of pressure and position parameters, the curvature corresponding to the current position parameter value of the execution unit;

The execution unit is used to adjust its own position parameter according to the position parameter adjustment amount.

Optionally, the control unit includes a storage module, an acquisition module, a calculation module, and a control module, where:

The storage module is used to store a sample data template; the sample data template includes different correspondences between the gas flow values and the curves, and the correspondence between different position parameter values and curvatures in each of the curves relationship;

The acquisition module is configured to acquire the curvature from the sample data template stored in the storage module according to the current gas flow value and the current position parameter value of the execution unit, and send it to the Calculation module

The calculation module is configured to calculate the product of the curvature obtained from the sample data template and the PID coefficient, and send it to the control module as the control coefficient;

The control module is configured to calculate and obtain the position parameter adjustment amount of the execution unit based on the difference value and the control coefficient, and output to the execution unit.

Optionally, the execution unit includes a pressure regulating valve for adjusting the exhaust flow rate of the chamber, and a vacuum device for extracting the internal gas of the chamber; wherein,

The position parameter is the valve position of the pressure regulating valve corresponding to its opening.

Optionally, the pressure regulating valve includes a butterfly valve, a needle valve or a ball valve.

Optionally, the chamber pressure control device further includes an input unit for receiving the target pressure value input by the user and sending it to the control unit.

Optionally, the detection unit is configured to detect the pressure of the chamber at the exhaust port as the actual pressure value;

Alternatively, the detection unit is configured to detect the difference between the internal pressure of the chamber and the atmospheric pressure outside the chamber as the actual pressure value.

As another technical solution, the present invention also provides a semiconductor device, including a reaction chamber, characterized in that it further includes a chamber pressure control device for controlling the pressure of the reaction chamber, and the chamber pressure control device Using the above-mentioned chamber pressure control device provided by the present invention, wherein:

The detection unit is used to detect the actual pressure value inside the reaction chamber and send it to the control unit; the execution unit is arranged at the exhaust port of the reaction chamber for The position parameter adjustment amount adjusts its own position parameter.

The beneficial effects of the present invention:

In the chamber pressure control method and device provided by the present invention, and the technical solution of the semiconductor equipment, while the closed-loop control of the chamber pressure is achieved through step S1, step S2, and step S4, the control coefficient is obtained through step S3. The control coefficient is the product of the curvature corresponding to the current position parameter value of the actuator and the preset PID (Proportion-Integral-Derivative) coefficient in the curve about the pressure and position parameters corresponding to the current gas flow value, that is , According to the corresponding relationship between the gas flow, pressure and the position parameter of the actuator, under different gas flow conditions, the PID coefficient can be finely adjusted in sections, so as to achieve rapid and stable control of the chamber pressure, so that It is stable within the preset range, which can improve the process quality and yield.

Description of the drawings

FIG. 1 is a flowchart of a method for controlling chamber pressure according to a first embodiment of the present invention;

Figure 2 is a graph of pressure and position parameters under a certain gas flow rate;

3 is a flow chart of a method for controlling chamber pressure according to a second embodiment of the present invention;

4 is a schematic block diagram of a chamber pressure control device provided by a third embodiment of the present invention;

Fig. 5 is a functional block diagram of a control unit adopted in the third embodiment of the present invention;

Fig. 6 is a structural diagram of a chamber pressure control device provided by a third embodiment of the present invention.

detailed description

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the chamber pressure control method and device and semiconductor equipment provided by the present invention will be described in detail below with reference to the accompanying drawings.

Please refer to FIG. 1, the chamber pressure control method provided by the first embodiment of the present invention includes the following steps:

S1, the actual pressure value inside the detection chamber.

In step S1, optionally, the pressure of the chamber at the exhaust port may be detected as the actual pressure value; or, the difference between the internal pressure of the chamber and the atmospheric pressure outside the chamber may also be detected as the actual pressure value. In other words, the chamber pressure control method provided in this embodiment may be applicable to an absolute pressure control method or a relative pressure control method.

S2: Calculate the difference between the actual pressure value and the preset target pressure value; and determine whether the difference exceeds the preset range, if it exceeds, proceed to step S3; if it does not exceed, then the process ends.

S3: Obtain a control coefficient, where the control coefficient is the product of the curvature corresponding to the current position parameter value of the execution unit and the preset PID coefficient in the curve about the pressure and the position parameter corresponding to the current gas flow value.

In step S3, each gas at a flow value (the gas flow value into the chamber) corresponds to a curve about the pressure and the position parameter of the actuator, that is, different gas flow values correspond to different pressure and execution The curve of the location parameter of the unit. As shown in Figure 2, the abscissa of each curve is the position parameter value of the execution unit (L1, L2,..., Ln); the ordinate is the position parameter value (L1, L2,..., Ln) One-to-one corresponding chamber pressure value (P1, P2,..., Pn). The curvature of the curve corresponding to each position parameter value (L1, L2,..., Ln) is the conversion coefficient (K1, K2,..., Kn) that represents the pressure change and the valve opening.

The aforementioned control coefficient is the product of the conversion coefficient corresponding to the current position parameter value of the execution unit and the preset PID (Proportion-Integral-Derivative) coefficient. The so-called PID coefficients refer to the proportional coefficients (Proportion), integral coefficients (Integral) and differential coefficients (Derivative) used to realize PID control, and PID control is realized by the following step S4. PID control is used in closed-loop control. It is used to calculate the control value (for example, the adjustment value of the execution unit) based on the system error, based on the proportional coefficient, integral coefficient, and differential coefficient, and the difference between the actual value and the expected value. The control quantity controls the execution unit.

S4: Calculate and obtain the position parameter adjustment amount of the execution unit based on the above difference and the control coefficient, and output it to the execution unit, and return to step S2.

The above-mentioned execution unit is used to adjust the pressure of the chamber. For example, the execution unit is a pressure regulating valve provided on the exhaust pipe of the chamber. In the process of the vacuum device extracting gas in the chamber, the pressure regulating valve adjusts the exhaust flow by adjusting the valve opening, so that the chamber pressure can be adjusted. Here, the position parameter value of the pressure regulating valve is the valve position corresponding to its opening.

Through the above steps S1, S2, and S4, a closed-loop control of the chamber pressure can be realized. At the same time, the control coefficient is obtained through step S3, and the control coefficient is the curve of the pressure and position parameters corresponding to the current gas flow value. The curvature corresponding to the current position parameter value of the execution unit and the preset PID coefficient Product, that is, according to the corresponding relationship between gas flow, pressure and position parameters, under different gas flow conditions, the PID coefficients can be finely adjusted in sections, that is, different gas flow values, different position parameter values The curvature of the corresponding curve is different, and the product of the curvature and the PID coefficient (ie, the control coefficient) is also different, so that the chamber pressure can be quickly and stably controlled to stabilize within the preset range, thereby improving the process quality and yield .

It is found through experiments that the chamber pressure control method provided by the embodiment of the present invention can control the chamber pressure with a precision of 0.02% F.S.

Optionally, the chamber pressure control method provided in this embodiment selects the position parameter range of the execution unit based on the PTL (Pressure to Location) strategy to achieve the purpose of minimizing the pressure fluctuation range, thereby improving process stability And repeatability.

For example, when the actuator is a pressure regulating valve, based on the valve's quick opening characteristics, that is, when the opening is small, the pressure regulating valve has a higher sensitivity to control pressure changes. When the valve position is close to the fully closed state (opening is 0° ), change the valve position, the pressure fluctuation is more obvious; when the valve position is within the range corresponding to the opening range of 30°-50°, change the valve position, the pressure fluctuation is smaller, and the pressure is more stable. The degree of influence on the process is relatively small; when the valve position is within the range corresponding to the value range of the opening degree greater than 60°, changing the valve position will basically have no effect on the pressure adjustment.

Based on the PTL (Pressure to Location) strategy, the initial value of the position parameter of the execution unit can be set in a range corresponding to the opening range of the pressure regulating valve; the opening range is 30°-50°. In this way, the position parameters of the execution unit can be adjusted in a stable area with small pressure fluctuations, so that the influence of pressure fluctuations on the process can be reduced.

FIG. 3 is a flowchart of a method for controlling chamber pressure according to a second embodiment of the present invention. Referring to FIG. 3, the chamber pressure control method provided by the second embodiment of the present invention is a further improvement made on the basis of the above-mentioned first embodiment. Specifically,

Before the above step S1, it also includes:

S0, pre-store the sample data template;

The sample data template includes the correspondence between different gas flow values and curves, and the correspondence between different position parameter values and curvatures in each curve.

In the entire process, different gas flow values (gas flow values into the chamber) can be stepped in different process time periods. For example, the entire process time is divided into four process time periods, and the four process time periods are respectively Corresponding to four gas flow values, 28L/min, 24L/min, 20L/min, and 16L/min. The process time period corresponding to different gas flow values can be the same or different. The predetermined time period is, for example, 110s. Optionally, according to process requirements, the gas flow rate value ranges from 3-50L/min.

According to the changes of the gas flow value mentioned above, multiple sets of data about pressure and position parameters can be collected, and the curves and curvatures about pressure and position parameters can be obtained by fitting the data based on the data, and the parameters reflecting flow, pressure and position can be constructed accordingly. The sample data template of the corresponding relationship is stored before the process.

On this basis, the above step S3 further includes:

S31, according to the current gas flow value and the current position parameter value of the execution unit, obtain the corresponding curvature from the sample data template;

It can be seen from the above that in the process of the process, when the current gas flow rate and current position parameter values are known, the corresponding curvature can be directly obtained from the sample data template, and the curvature and PID coefficients can be calculated product. In this way, not only the control accuracy is high, but also the response speed is fast.

As another technical solution, please refer to FIGS. 4 to 6 together. The chamber pressure control device provided by the third embodiment of the present invention includes a detection unit 2, a control unit 5, and an execution unit 3, wherein the detection unit 2 uses It detects the actual pressure value inside the chamber and sends it to the control unit 5. The detection unit 2 is, for example, a pressure gauge.

Optionally, the detection unit 2 is used to detect the pressure of the chamber 1 at the exhaust port as the actual pressure value; or the detection unit 2 is used to detect the difference between the internal pressure of the chamber 1 and the atmospheric pressure outside the chamber as the actual pressure Pressure value. In other words, the chamber pressure control device provided in this embodiment can be applied to an absolute pressure control system or a relative pressure control system.

The control unit 5 is used to calculate the difference between the actual pressure value and the preset target pressure value; and determine whether the difference exceeds the preset range, if it exceeds, obtain the control coefficient, and calculate the execution unit based on the difference and the control coefficient The position parameter adjustment value of 3 is output to the execution unit 3; the control coefficient is the product of the curvature and the preset PID coefficient. The curvature is the curvature corresponding to the current position parameter value of the execution unit 3 in the curve about the pressure and the position parameter corresponding to the current gas flow value. Optionally, the control unit 5 is a microprocessor.

The execution unit 3 is used to adjust its own position parameter according to the position parameter adjustment amount from the control unit 5.

In this embodiment, as shown in Figure 6, the execution unit 3 includes a pressure regulating valve 31 for regulating the exhaust flow of the chamber 1, and a vacuum device 32 for extracting the internal gas of the chamber 1; wherein the pressure The regulating valve 31 is arranged on the exhaust pipe 7, which adjusts the valve opening degree by adjusting its valve position, so as to adjust the gas flow in the exhaust pipe 7, thereby realizing the pressure adjustment in the chamber. Therefore, the position parameter of the above-mentioned execution unit 3 is the valve position of the pressure regulating valve 31 corresponding to its opening, and different valve positions correspond to different valve openings. The vacuum device 32 is used for exhausting the gas in the chamber 1 into the exhaust pipe 7 by pumping. The vacuum device 32 is, for example, a vacuum generator.

Optionally, the pressure regulating valve 31 includes a butterfly valve, a needle valve, a ball valve, or the like. Specifically, a pressure regulating valve with automatic control function is usually provided with a motor for driving the valve (butterfly valve, needle valve, ball valve, etc.) to move, and the control unit 5 realizes the adjustment of the valve position by sending a control signal to the motor.

Preferably, as shown in FIG. 5, the control unit 5 includes a storage module 51, an acquisition module 52, a calculation module 53, and a control module 54, wherein the storage module 51 is used to store sample data templates, which include different gas flow rates. The corresponding relationship between the value and the curve, and the corresponding relationship between different position parameter values and curvatures in each curve. The obtaining module 52 is configured to obtain the corresponding curvature from the sample data template stored in the storage module 51 according to the current gas flow value and the current position parameter value of the execution unit, and send it to the calculation module 53. The calculation module 53 is used to calculate the product of the curvature obtained from the sample data template and the PID coefficient, and send it as a control coefficient to the control module 54; the control module 54 is used to calculate the position of the execution unit 3 based on the difference and the control coefficient The parameter adjustment amount is output to the execution unit 3.

During the process, by pre-storing the above-mentioned sample data model in the storage module 51, when the current gas flow rate and the current position parameter value are known, the acquisition module 52 can directly acquire it from the sample data template. Corresponding curvature, and use the calculation module 53 to calculate the product of the curvature and the PID coefficient. In this way, not only the control accuracy is high, but also the response speed is fast.

Optionally, the chamber pressure control device further includes an input unit for receiving the target pressure value input by the user and sending it to the control unit 5. In this way, the user can freely input the desired value of the pressure as needed.

In summary, the chamber pressure control device provided by this embodiment can achieve rapid and stable control of the chamber pressure to stabilize it within a preset range, thereby improving process quality and yield.

As another technical solution, an embodiment of the present invention also provides a semiconductor device, which includes a reaction chamber and a chamber pressure control device for controlling the pressure of the reaction chamber. The chamber pressure control device adopts the embodiment of the present invention. The above-mentioned chamber pressure control device is provided. In the semiconductor device, the detection unit is used to detect the actual pressure value inside the reaction chamber and send it to the control unit; the execution unit is set at the exhaust port of the reaction chamber and is used to adjust itself according to the position parameter adjustment amount Positional parameters. As shown in FIG. 6, the semiconductor device includes a reaction chamber 1 and various process gas paths (O2 gas path, H2 gas path, N2 gas path, etc.) for inputting process gas into the reaction chamber. In the semiconductor device, the detection unit can communicate with the exhaust port of the reaction chamber through one end of the three-way joint, and the execution unit can communicate with the exhaust port of the reaction chamber through one end of the three-way interface in the three-way joint.

The semiconductor device provided in this embodiment, by adopting the chamber pressure control device provided in the embodiment of the present invention, can achieve rapid and stable control of the chamber pressure to stabilize it within a preset range, thereby improving process quality and finished products rate.

It can be understood that the above implementations are merely exemplary implementations used to illustrate the principle of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

A method for controlling chamber pressure is characterized in that it comprises the following steps:

S1, the actual pressure value inside the detection chamber;

S2: Calculate the difference between the actual pressure value and the preset target pressure value; and determine whether the difference exceeds the preset range, if it exceeds, proceed to step S3; if it does not exceed, then the process ends;

S3. Obtain a control coefficient, where the control coefficient is the product of the curvature and the preset PID coefficient, where the curvature is: in the curve of the pressure and the position parameter of the actuator corresponding to the current gas flow value, and The curvature corresponding to the current position parameter value of the execution unit;

S4: Calculate and obtain the position parameter adjustment amount of the execution unit based on the difference value and the control coefficient, and output it to the execution unit, and return to step S2.
The chamber pressure control method according to claim 1, characterized in that, before said step S1, further comprising:

S0, pre-store the sample data template;

Wherein, the sample data template includes different correspondences between the gas flow values and the curves, and different correspondences between the position parameter values and curvatures in each of the curves;

The step S3 further includes:

S31: Acquire the curvature from the sample data template according to the current gas flow value and the current position parameter value of the execution unit;

S32: Calculate the product of the curvature obtained from the sample data template and the PID coefficient.
The chamber pressure control method according to claim 1 or 2, wherein the execution unit comprises a pressure regulating valve, and the position parameter of the execution unit is the valve position of the pressure regulating valve corresponding to its opening.
The chamber pressure control method according to claim 3, wherein the initial value of the position parameter of the execution unit is set in a range corresponding to the value range of the opening of the pressure regulating valve; The range of degrees is 30°-50°.
The chamber pressure control method according to claim 1 or 2, wherein the gas flow value has a value range of 3-50 L/min.
The chamber pressure control method according to claim 1, wherein in the step S1, the pressure of the chamber at the exhaust port is detected as the actual pressure value;

Alternatively, the difference between the internal pressure of the chamber and the atmospheric pressure outside the chamber is detected as the actual pressure value.
A chamber pressure control device is characterized by comprising a detection unit, a control unit and an execution unit, wherein:

The detection unit is used to detect the actual pressure value inside the chamber and send it to the control unit;

The control unit is used to calculate the difference between the actual pressure value and a preset target pressure value; and determine whether the difference exceeds a preset range, and if it exceeds, obtain a control coefficient, and based on the difference sum The control coefficient is calculated. The position parameter adjustment amount of the execution unit is output to the execution unit; the control coefficient is the product of the curvature and the preset PID coefficient, wherein the curvature is: and the current gas flow value The curvature corresponding to the current position parameter value of the execution unit in the corresponding curve about the pressure and the position parameter;

The execution unit is used to adjust its own position parameter according to the position parameter adjustment amount.
The chamber pressure control device according to claim 7, wherein the control unit includes a storage module, an acquisition module, a calculation module, and a control module, wherein:

The storage module is used to store a sample data template; the sample data template includes different correspondences between the gas flow values and the curves, and the correspondence between different position parameter values and curvatures in each of the curves relationship;

The acquisition module is configured to acquire the curvature from the sample data template stored in the storage module according to the current gas flow value and the current position parameter value of the execution unit, and send it to the Calculation module

The calculation module is configured to calculate the product of the curvature obtained from the sample data template and the PID coefficient, and send it to the control module as the control coefficient;

The control module is configured to calculate and obtain the position parameter adjustment amount of the execution unit based on the difference value and the control coefficient, and output to the execution unit.
The chamber pressure control device according to claim 7 or 8, wherein the execution unit includes a pressure regulating valve for adjusting the exhaust flow rate of the chamber, and a pressure regulating valve for extracting the inside of the chamber Gas vacuum device; among them,

The position parameter is the valve position of the pressure regulating valve corresponding to its opening.
The chamber pressure control device according to claim 9, wherein the pressure regulating valve comprises a butterfly valve, a needle valve or a ball valve.
The chamber pressure control device according to claim 7, wherein the chamber pressure control device further comprises an input unit for receiving the target pressure value input by the user and sending it to the control unit .
8. The chamber pressure control device according to claim 7, wherein the detection unit is used to detect the pressure of the chamber at the exhaust port as the actual pressure value;

Alternatively, the detection unit is configured to detect the difference between the internal pressure of the chamber and the atmospheric pressure outside the chamber as the actual pressure value.
A semiconductor device comprising a reaction chamber, characterized in that it further comprises a chamber pressure control device for controlling the pressure of the reaction chamber, and the chamber pressure control device adopts any one of claims 7-12 The chamber pressure control device, wherein,

The detection unit is used to detect the actual pressure value inside the reaction chamber and send it to the control unit; the execution unit is arranged at the exhaust port of the reaction chamber for The position parameter adjustment amount adjusts its own position parameter.