Gas flow control valve, gas conveying device and gas supply method

Abstract

The invention provides a gas flow control valve, a gas conveying device and a gas supply method, the gas flow control valve comprises a first valve body and a second valve body, the first valve body and the second valve body are oppositely arranged and parallel to each other, and a gas flow channel of reaction gas is formed between the first valve body and the second valve body; the distance between the first valve body and the second valve body is defined as the valve body opening degree of the gas flow control valve; the driving device is made of a piezoelectric ceramic material and is used for driving the second valve body to move towards or away from the first valve body, and the opening degree of the valve body is adjusted by adjusting the voltage applied to the driving device; the position sensor is used for detecting the opening degree of the valve body. The gas flow control valve has the advantages that the opening degree of the valve body can be accurately detected, the control precision and the response speed of the gas flow control valve are improved, and reaction gas with corresponding flow can be accurately conveyed to different areas in a reaction cavity according to a target gas flow ratio in one-to-multiple paths.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a gas flow control valve, a gas delivery device and a gas supply method. Background Art

[0002] In semiconductor manufacturing, many key steps are carried out in a reaction chamber (also called a reaction chamber or reactor), which is a closed and stable environment to ensure the accuracy and repeatability of the process.

[0003] Currently, the wafer size has generally reached 12 inches, and even larger sizes are under development. The reaction gas is divided into multiple paths by a gas splitter set outside the reaction chamber, and the volume flow ratio of the multiple reaction gases is adjusted. The multiple reaction gases are injected into different areas of the reaction chamber to obtain a uniform processing effect on a large area of ​​the wafer surface.

[0004] Existing gas flow dividers mostly use piezoelectric ceramic valves to adjust the flow of each reaction gas. The valve position (i.e., valve opening) of the piezoelectric ceramic valve is adjusted by adjusting the driving voltage of the piezoelectric ceramic valve, thereby adjusting the gas flow in the pipeline where the piezoelectric ceramic valve is located.

[0005] However, there is uncertainty between the driving voltage and the valve body position, and there are also large differences between different piezoelectric ceramic valves. Therefore, adjusting the valve body opening by adjusting the driving voltage has large deviations and uncontrollability, and the response speed of the volume flow ratio control of each reaction gas is slow, and the volume flow ratio takes a long time to reach a steady state. Summary of the invention

[0006] The purpose of the present invention is to provide a gas flow control valve, a gas delivery device and a gas supply method, which can accurately detect the valve body opening of the gas flow control valve, adjust the voltage applied to the gas flow control valve according to the detection result, and effectively improve the control accuracy of the gas flow control valve. Through the present invention, it is possible to achieve 1-way multi-channel, accurately deliver the corresponding flow of reaction gas to different areas in the reaction chamber according to the target gas flow ratio, and the entire gas delivery device can quickly reach a steady state.

[0007] In order to achieve the above object, the present invention provides a gas flow control valve, comprising: A first valve body and a second valve body, wherein the first valve body and the second valve body are arranged opposite to each other and parallel to each other, and a gas flow channel for the reaction gas is formed therebetween; and a distance between the first valve body and the second valve body is defined as a valve body opening of the gas flow control valve; A driving device, which is made of piezoelectric ceramic and is used to drive the second valve body to move toward or away from the first valve body; the opening of the valve body is adjusted by adjusting the voltage applied to the driving device; A position sensor, used to detect the opening of the valve body; the position sensor includes a capacitance detection device; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body.

[0008] Optionally, the first valve body or the second valve body is electrically connected to a pulse power supply; the capacitance detection device detects the capacitance value by detecting the pulse width or voltage value of one of the first valve body and the second valve body that is not electrically connected to the pulse power supply.

[0009] Optionally, the position sensor further includes: a first conductive element and a second conductive element; The first conductive element or the second conductive element is electrically connected to a pulse power source; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

[0010] Optionally, the capacitance detection device detects the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element by detecting the pulse width or voltage value of one of the first conductive element and the second conductive element that is not electrically connected to the pulse power supply.

[0011] Optionally, the frequency of the pulse power supply is greater than or equal to 2KHZ.

[0012] Optionally, the gas flow control valve further includes a sealing gasket, which is disposed on a surface of the first valve body facing the second valve body, or on a surface of the second valve body facing the first valve body.

[0013] Optionally, the sealing gasket is made of flexible insulating material.

[0014] The present invention also provides a gas delivery device, comprising: A plurality of gas flow distribution pipelines are used to inject reaction gas into different areas in the reaction chamber; A plurality of gas flow control valves according to the present invention are respectively arranged on a plurality of gas flow distribution pipelines; the position sensor of the gas flow control valve comprises a capacitance detection device, and the capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body; The controller is configured to adjust the voltage applied to the corresponding drive device based on the target gas flow ratio of the multiple gas diversion and delivery pipelines and the valve body opening detected by the position sensor, until the valve body opening detected by the position sensor reaches a target valve body opening that can achieve the target gas flow ratio; when the capacitance value detected by the capacitance detection device reaches a preset target capacitance value, the controller determines that the gas flow control valve has reached the target valve body opening.

[0015] Optionally, the position sensor further includes: a first conductive element and a second conductive element; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

[0016] Optionally, the database of the controller stores: the target gas flow ratio, and the target capacitance value of each gas flow control valve corresponding to the target gas flow ratio; and the controller obtains the target capacitance value by querying the database.

[0017] Optionally, one of the multiple gas flow control valves is always kept in a fully open state.

[0018] Optionally, the gas diversion delivery pipeline where the fully-open gas flow control valve is located has a maximum target gas flow rate.

[0019] Optionally, the moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment; the controller is configured to adopt a proportional-integral-differential adjustment method to continuously control the valve body opening of the gas flow control valve from the first moment to achieve that the difference between the detected valve body opening and the target valve body opening is less than a preset difference threshold.

[0020] Optionally, the gas delivery device further includes a plurality of gas flow meters, which are respectively arranged on the plurality of gas diversion delivery pipelines; the gas flow meters are located downstream of the corresponding gas flow control valves.

[0021] Optionally, the gas delivery device also includes a barometer and a gas delivery main pipeline; the gas delivery main pipeline is connected between the reaction gas supply source and the plurality of gas branch delivery pipelines; the barometer is arranged on the gas delivery main pipeline to measure the gas pressure value in the gas delivery main pipeline.

[0022] Optionally, the barometer signal is connected to the controller, and when the air pressure value exceeds a set air pressure threshold, the controller generates an alarm message.

[0023] The present invention also provides a gas supply method, which is implemented by using the gas delivery device according to the present invention, comprising the steps of: The position sensor detects the valve body opening of the corresponding gas flow control valve in real time; the position sensor includes a capacitance detection device, and the capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body; The controller adjusts the voltage applied to the corresponding drive device based on the target gas flow ratio of multiple gas diversion delivery pipelines and the valve body opening detected by the position sensor until the valve body opening detected by the position sensor reaches the target valve body opening that can achieve the target gas flow ratio; when the capacitance value detected by the capacitance detection device reaches a preset target capacitance value, the controller determines that the gas flow control valve has reached the target valve body opening.

[0024] Optionally, the position sensor further includes a first conductive element and a second conductive element; The first conductive element or the second conductive element is electrically connected to a pulse power source; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

[0025] Optionally, the database of the controller stores: the target gas flow ratio, and the target capacitance value of each gas flow control valve corresponding to the target gas flow ratio; and the controller obtains the target capacitance value by querying the database.

[0026] Optionally, the moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment, and the method further includes the steps of: Starting from the first moment, the controller adopts the proportional-integral-differential regulation method to continuously control the valve body opening of the gas flow control valve, so that the difference between the detected valve body opening and the target valve body opening is less than a preset difference threshold.

[0027] Optionally, one of the multiple gas flow control valves is always kept in a fully open state.

[0028] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: 1) The gas flow control valve, gas delivery device and gas supply method of the present invention can accurately detect the valve body opening of the gas flow control valve on each delivery pipeline, realize 1-to-2-way, or even 1-to-multi-way, and deliver the corresponding flow of reaction gas to different areas in the reaction chamber, effectively improving the control accuracy of the flow of reaction gas in each route. Improve the consistency of the processing rate of different areas on the wafer surface, and greatly improve the yield rate of wafer processing.

[0029] 2) The present invention pre-learns and stores the correspondence between the target gas flow ratio and the target capacitance value of each gas flow control valve, and obtains the target capacitance value of the corresponding flow path by searching the database, so as to accurately deliver the reaction gas to the reaction chamber according to the target gas flow ratio. Adjusting the valve body opening according to the searched target capacitance value not only improves the control accuracy of the valve body opening, but also consumes little time and has a fast response speed. The present invention is not affected by the differences in gas flow control valves, has lower requirements for the selection of gas flow control valves, and has better robustness.

[0030] 3) In the process of adjusting the gas flow of each path, the present invention always keeps a gas flow control valve fully open, effectively avoiding the sudden pressure change when the reaction gas enters the reaction chamber, and no "impact" airflow will appear in the reaction chamber, and the pressure disturbance in the reaction chamber is small. The present invention greatly improves the yield rate of wafer processing and the controllability of the process.

[0031] 4) In the present invention, a pulse electrical signal is provided to one of the first valve body and the second valve body to form an equivalent capacitor between the first valve body and the second valve body. By measuring the pulse width or voltage value of the one of the first valve body and the second valve body to which the pulse electrical signal is not applied, the capacitance value of the equivalent capacitor can be accurately measured. The calculation formula of the capacitance value C of the equivalent capacitor is: C=εS∕4πkd. S is the area of ​​the first valve body, ε is the dielectric constant, k is the electrostatic force constant, S, ε, and k are all known quantities, so that by detecting the capacitance value C, the distance d between the first valve body and the second valve body can be obtained, that is, the valve body opening of the gas flow control valve can be detected. The detection process is simple and easy to implement. Compared with judging the valve body opening based on the voltage applied to the gas flow control valve, the present invention has higher reliability.

[0032] 5) In the present invention, a first conductive element (electrically insulated from the first valve body) is provided on the first valve body, and a second conductive element (electrically insulated from the second valve body) is provided on the second valve body, and the valve body opening is detected by detecting the capacitance value of the equivalent capacitance formed by the first conductive element and the second conductive element. Since there is no electrical contact between the first conductive element, the second conductive element and other elements, the accuracy of the detection result is further improved.

[0033] 6) When the valve opening reaches the target valve opening, if the driving voltage (voltage applied to the driving device) remains unchanged, the valve opening will continue to change. This is due to the slow response speed of the piezoelectric ceramic material. The present invention also adopts a proportional-integral-differential method to continuously control the valve opening of the gas flow control valve from the moment the detected valve opening reaches the target valve opening. This effectively overcomes the problem of deviation between the actual gas flow ratio and the target gas flow ratio caused by the hysteresis effect of the piezoelectric ceramic material, and enables the valve opening to stabilize at the target valve opening more quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the description. Obviously, the drawings described below are an embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work: Figure 1 is a schematic diagram of a plasma processing device; Figure 2 A schematic diagram showing uncertainty between the valve body opening of a piezoelectric ceramic valve and the voltage applied to the piezoelectric ceramic valve; Figure 3 A schematic diagram of a gas flow control valve in a closed state in an embodiment of the present invention; Figure 4 is a schematic diagram of a gas flow control valve in an open state in an embodiment of the present invention; Figure 5 A schematic diagram of a gas flow control valve provided with a sealing gasket in a preferred embodiment of the present invention; Figure 6 A schematic diagram of a position sensor detecting the opening of a valve body in one embodiment of the present invention; Figure 7 A schematic diagram of a position sensor detecting the opening of a valve body in an embodiment of the present invention; Figure 8 Schematic diagram of a gas delivery device injecting reaction gas into multiple areas in a reaction chamber in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0037] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0038] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0039] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0040] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0041] Figure 1 , a plasma processing device 1 is shown, which is an inductively coupled plasma (ICP) processing device. An inductively coupled plasma processing device is a device that couples the energy of a radio frequency power source into a reaction chamber in the form of a magnetic field via an inductive coil, thereby generating plasma for etching.

[0042] like Figure 1As shown, the plasma processing device 1 includes a vacuum reaction chamber 10, and the reaction chamber 10 includes a substantially cylindrical reaction chamber side wall 101 made of metal material, and an opening 102 is provided on the reaction chamber side wall 101 for accommodating the wafer W to enter and exit. A base 120 is provided at the bottom of the reaction chamber 10, and an electrostatic chuck 121 is provided on the base. An electrostatic electrode 122 is provided inside the electrostatic chuck 121 for generating electrostatic suction force to support and fix the wafer W to be processed during the process.

[0043] An insulating window 117 (usually a ceramic dielectric material) is arranged above the side wall 101 of the reaction chamber, and an inductive coupling coil 115 is arranged above the insulating window 117. The RF power source 140 applies RF voltage to the inductive coupling coil 115 through the RF matching network 141. The RF power of the RF power source 140 drives the inductive coupling coil 115 to generate a strong high-frequency alternating magnetic field, so that the reaction gas in the reaction chamber 10 is ionized to generate plasma. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. The above active particles can undergo various physical and chemical reactions with the surface of the wafer W to be processed, so that the morphology of the surface of the wafer W changes, that is, the etching process is completed.

[0044] An inner liner 105 is disposed inside the reaction chamber 10 to protect the inner wall of the reaction chamber from being corroded by the plasma. An exhaust pump 107 is also disposed below the reaction chamber 10 to exhaust the reaction byproducts from the reaction chamber 10 and maintain the vacuum environment of the reaction chamber 10 .

[0045] However, due to various reasons such as gas delivery, electric field effect or uneven exhaust, it is easy for the plasma to have different distribution densities in different areas of the reaction chamber 10, thereby producing different etching speeds in different areas of the surface of the wafer W, which may cause subsequent processes such as ion implantation to be affected, greatly reducing the yield rate of wafer W processing.

[0046] In order to solve this problem, the reaction gas is usually divided into multiple paths with different flow rates. The multiple reaction gases are delivered to different areas in the reaction chamber 10 according to the target gas flow ratio to achieve uniform plasma density distribution in the reaction chamber 10, thereby improving the uniformity of the surface treatment of the entire wafer W.

[0047] Figure 1 FIG. 1 shows that the reaction gas is delivered to different areas in the reaction chamber 10 by a one-way multi-path method. Figure 1As shown, a plurality of gas injection ports 108 are respectively arranged at one end of the reaction chamber side wall 101 close to the insulating window 117 and the central area of ​​the insulating window 117, and are respectively used to deliver reaction gas to the edge area (close to the reaction chamber side wall 101) and the central area in the reaction chamber 10. The gas delivery device gas circuit is connected and arranged between the reaction gas source 180 and the plurality of gas injection ports 108, and comprises: a gas delivery main pipeline 191, a plurality of gas diversion delivery pipelines 192 and a plurality of gas flow control valves 160. The input ends of the plurality of gas diversion delivery pipelines 192 are connected to the output ends of the gas delivery main pipeline 191, and the output ends of the plurality of gas diversion delivery pipelines 192 are respectively connected to the plurality of gas injection ports 108. The plurality of gas flow control valves 160 are respectively arranged on the plurality of gas diversion delivery pipelines 192, and the flow of reaction gas delivered to the corresponding area in the reaction chamber 10 is adjusted by adjusting the valve body opening of the corresponding gas flow control valve 160.

[0048] The gas flow control valve 160 in the industry usually adopts a piezoelectric ceramic valve, which has the advantages of small size and corrosion resistance. The valve body opening of the piezoelectric ceramic valve can be adjusted by adjusting the voltage applied to the piezoelectric ceramic valve. Figure 2 As shown, there is uncertainty between the voltage applied to the piezoelectric ceramic valve and the valve body opening, and the reasons include: ① The nonlinear relationship between the voltage and the valve body opening. ② During the voltage rise and fall process, the valve body opening corresponding to the same voltage is different. ③ The piezoelectric ceramic material causes the piezoelectric performance to decline during long-term use. In addition, there are large differences between different piezoelectric ceramic valves, including: starting voltage (the minimum voltage to open the valve body), cut-off voltage (when the voltage applied to the piezoelectric ceramic valve exceeds the cut-off voltage, the valve body opening no longer changes), and the adjustable range of the valve body opening. The above uncertainties and differences will cause the gas flow ratio of the multi-channel reaction gas to be different from the target gas flow ratio, affecting the processing effect of wafer W.

[0049] On the other hand, the piezoelectric ceramic valve has a slow response speed and takes a long time to reach a steady state. When the voltage applied to the piezoelectric ceramic valve stops increasing (decreasing), the valve body opening continues to increase (decrease) within a certain period of time. This not only reduces the efficiency of wafer W processing, but also causes the control accuracy of the gas flow to fail to meet the requirements, affecting the reliability of the gas delivery device.

[0050] In order to solve the above problems, the present embodiment provides a gas flow control valve, a gas delivery device and a gas supply method, which can accurately detect the valve body opening of the gas flow control valve, adjust the voltage applied to the gas flow control valve according to the detection result, and effectively improve the control accuracy of the gas flow control valve. Through the present invention, it is possible to achieve 1-to-2-way, 1-to-3-way, 1-to-4-way or even 1-to-more-way, accurately deliver the corresponding flow of reaction gas to different areas in the reaction chamber 10 according to the target gas flow ratio, and the entire gas delivery device can quickly reach a steady state.

[0051] like Figure 3 , Figure 4 As shown, the gas flow control valve 260 of this embodiment includes: a first valve body 261, a second valve body 262, a driving device 263 and a position sensor ( Figure 3 , Figure 4 not shown).

[0052] like Figure 3 , Figure 4 As shown, the first valve body 261 and the second valve body 262 are arranged opposite to each other and parallel to each other. Figure 4 As shown, when the gas flow control valve 260 is opened, a gas flow channel for the reaction gas is formed between the first valve body 261 and the second valve body 262. The distance between the first valve body 261 and the second valve body 262 is defined as the valve body opening of the gas flow control valve 260.

[0053] In a preferred embodiment, Figure 5 As shown, the gas flow control valve 260 also includes a sealing gasket 265, which is made of a flexible insulating material (for example, Teflon). The sealing gasket 265 is disposed on the surface of the first valve body 261 facing the second valve body 262. Alternatively, the sealing gasket 265 can also be disposed on the surface of the second valve body 262 facing the first valve body 261. When the gas flow control valve 260 is closed, the sealing gasket 265 can not only enhance the air tightness between the first valve body 261 and the second valve body 262 and prevent gas from leaking from between the first valve body 261 and the second valve body 262, but also reduce the impact force between the first valve body 261 and the second valve body 262, which is beneficial to prolonging the service life of the gas flow control valve 260.

[0054] like Figure 3 , Figure 4As shown, the driving device 263 penetrates the first valve body 261 and is fixedly connected to the second valve body 262. The driving device 263 is made of piezoelectric ceramic material, which has the characteristic of deforming after being energized. The deformation of the driving device 263 is controlled by adjusting the voltage applied to the driving device 263. When the driving device 263 is deformed, it will push the second valve body 262 to move, so that a gap is formed between the first valve body 261 and the second valve body 262. The gap is the valve body opening. For the convenience of subsequent description, the voltage applied to the driving device 263 is referred to as the driving voltage.

[0055] When the driving device 263 is not powered, or the driving device 263 is powered and the driving voltage is less than the starting voltage of the gas flow control valve 260, as shown in FIG. Figure 3 As shown, the driving device 263 will not be deformed, the first valve body 261 and the second valve body 262 are tightly fitted together under the action of the elastic element (not shown in the figure), and the gas flow control valve 260 is in a fully closed state.

[0056] When the voltage applied to the driving device 263 is greater than or equal to the starting voltage of the gas flow control valve 260, as Figure 4 As shown, the driving device 263 generates a corresponding deformation in a direction perpendicular to the second valve body 262, thereby driving the second valve body 262 to move in a direction away from the first valve body 261, and the gas flow control valve 260 opens. The valve body opening is positively correlated with the voltage value of the driving voltage, that is, the greater the driving voltage, the greater the valve body opening, and conversely, the smaller the driving voltage, the smaller the valve body opening. The driving device 263 retracts after power is cut off, and the second valve body 262 returns to Figure 3 The gas flow control valve 260 returns to the fully closed state.

[0057] Due to the characteristics of piezoelectric materials, there is uncertainty between the driving voltage and the valve body opening: there is no linear relationship between the driving voltage and the valve body opening, and there is no good formula to fit the relationship between the driving voltage and the valve body opening. During the rise and fall of the driving voltage, the same driving voltage corresponds to different valve body openings. The differences between different gas flow control valves 260 are also very large. Therefore, it is unreliable to judge the valve body opening of the gas flow control valve 260 based on the driving voltage provided to the gas flow control valve 260.

[0058] The first valve body 261 and the second valve body 262 are made of conductive material, such as stainless steel. Figure 6As shown (the driving device 263 is not shown), by applying a pulse electrical signal (with a frequency greater than or equal to 2KHZ) to any one of the first valve body 261 and the second valve body 262, an equivalent capacitor (referred to as a first equivalent capacitor) is formed between the first valve body 261 and the second valve body 262, and the first valve body 261 and the second valve body 262 can be regarded as two plates of the first equivalent capacitor.

[0059] In one embodiment, Figure 6 As shown, the position sensor includes a capacitance detection device 230, which is used to detect the pulse width of one of the first valve body 261 and the second valve body 262 to which the pulse electrical signal is not applied, and calculate the capacitance value C of the first equivalent capacitor based on the pulse width. The detection process of the capacitance value C is simple, the detection accuracy is high and it is easy to implement. Calculating the capacitance value based on the detected pulse width is a prior art and will not be described in detail here.

[0060] The capacitance value of the first equivalent capacitor is C=εS∕4πkd. ε is the dielectric constant of the dielectric between the first valve body 261 and the second valve body 262, S is the plate area, d is the valve body opening, and k is the electrostatic force constant. According to the expression of the capacitance value C, it can be known that the capacitance value C can accurately reflect the valve body opening d. Based on the detected capacitance value C, it is judged whether the gas flow control valve 260 reaches the target valve body opening, and then the driving voltage of the gas flow control valve 260 is adjusted. It has higher reliability, can greatly improve the control accuracy of the gas flow control valve 260, and is not affected by the differences of the gas flow control valve 260.

[0061] In another embodiment, the capacitance detection device 230 is used to detect the voltage value of one of the first valve body 261 and the second valve body 262 to which the pulse electrical signal is not applied, and calculate the capacitance value C based on the voltage value. Calculating the capacitance value based on the detected voltage value is a prior art and will not be described in detail here.

[0062] However, there may be electrical contact between the first valve body 261 , the second valve body 262 and the valve seat and the driving device 263 , which may affect the accuracy of the detection result of the capacitance value C.

[0063] like Figure 7 As shown, in this embodiment, the position sensor includes: a capacitance detection device 230 , a first conductive element 231 and a second conductive element 232 .

[0064] like Figure 7As shown in FIG. 2 (the driving device 263 is not shown), the first conductive element 231 passes through the first valve body 261, and an insulating material 233 (such as Teflon) is filled between the first conductive element 231 and the first valve body 261, so that the first conductive element 231 is electrically insulated from the first valve body 261. The second conductive element 232 passes through the second valve body 262, and an insulating material 233 is filled between the second conductive element 232 and the second valve body 262, so that the second conductive element 232 is electrically insulated from the second valve body 262. The first conductive element 231 and the second conductive element 232 are arranged opposite to each other, and by applying a pulse electrical signal (with a frequency greater than or equal to 2KHZ) to any one of the first conductive element 231 and the second conductive element 232, an equivalent capacitor (referred to as a second equivalent capacitor) is formed between the first conductive element 231 and the second conductive element 232, and the first conductive element 231 and the second conductive element 232 can be regarded as two plates of the second equivalent capacitor. The capacitance detection device 230 detects the pulse width or voltage value of one of the first conductive element 231 and the second conductive element 232 to which no pulse electrical signal is applied, thereby detecting the capacitance value of the second equivalent capacitor and further detecting the valve body opening.

[0065] Since there is no electrical contact between the first conductive element 231, the second conductive element 232 and other elements of the gas flow control valve 260, the capacitance value of the second equivalent capacitance formed by the first conductive element 231 and the second conductive element 232 can more accurately reflect the valve body opening than the capacitance value of the first equivalent capacitance formed by the first valve body 261 and the second valve body 262.

[0066] In another embodiment, the position sensor may also be an LVDT (Linear Variable Displacement Transducer) or a laser rangefinder to directly measure the distance between the first valve body and the second valve body. However, these two methods make significant structural changes to the first valve body 261 and the second valve body 262, greatly increasing the economic cost, and the measurement accuracy is slightly lower.

[0067] This embodiment also provides a gas delivery device. Figure 8 As shown, the gas delivery device includes: a gas delivery main pipeline 291, a plurality of gas branch delivery pipelines 292, a plurality of gas flow control valves 260 and a controller 220 as described in the present invention.

[0068] The gas delivery main pipeline 291 is connected between the reaction gas supply source 280 and the plurality of gas branch delivery pipelines 292. Figure 8 As shown, the plurality of gas flow distribution pipelines 292 are respectively used to inject reaction gas into different areas in the reaction chamber 20. The plurality of gas flow control valves 260 are respectively disposed on the plurality of gas flow distribution pipelines 292. Figure 8 The reaction chamber 20 is a reaction chamber of an inductively coupled plasma processing device, and the gas delivery device of the present invention is also suitable for injecting reaction gas into the reaction chamber of other wafer processing equipment.

[0069] The controller 220 is configured to adjust the voltage applied to the drive device 263 of the corresponding gas flow control valve 260 based on the target gas flow ratio of multiple gas diversion delivery pipelines 292 and the valve body opening detected by the position sensor of the gas flow control valve 260, until the valve body opening detected by the position sensor reaches the target valve body opening that can achieve the target gas flow ratio.

[0070] The gas delivery device of the present invention can accurately detect the valve body opening of each gas flow control valve 260, effectively improving the control accuracy of each reaction gas flow, realizing 1-to-2-way, or even 1-to-multi-way, and delivering the required flow of reaction gas to different areas in the reaction chamber 20, which helps to improve the consistency of the processing rate of different areas on the surface of the wafer W and improve the yield rate of wafer W processing.

[0071] In one embodiment, Figure 6 As shown, a pulse electric signal is applied to the first valve body 261 or the second valve body 262 of the gas flow control valve 260, so that the first valve body 261 and the second valve body 262 form an equivalent capacitor. The position sensor includes a capacitance detection device 230, and the capacitance detection device 230 detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed by the first valve body 261 and the second valve body 262. When the capacitance value detected by the capacitance detection device 230 reaches a preset target capacitance value, the controller 220 determines that the gas flow control valve 260 reaches the target valve body opening.

[0072] To prevent the electrical contact between the first valve body 261, the second valve body 262 and other components from affecting the detection results, Figure 7 As shown, the position sensor in this embodiment includes: a first conductive element 231 , a second conductive element 232 and a capacitance detection device 230 .

[0073] The first conductive element 231 passes through the first valve body 261 and is electrically insulated from the first valve body 261, and the second conductive element 232 passes through the second valve body 262 and is electrically insulated from the second valve body 262. The second conductive element 232 is arranged opposite to the first conductive element 231. By applying a pulse electrical signal to the first conductive element 231 or the second conductive element 232, an equivalent capacitor is formed between the first conductive element 231 and the second conductive element 232. The capacitance detection device 230 detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed by the first conductive element 231 and the second conductive element 232. When the capacitance value detected by the capacitance detection device 230 reaches a preset target capacitance value, the controller 220 determines that the gas flow control valve 260 reaches the target valve body opening.

[0074] In this embodiment, Figure 8 As shown, the gas delivery device further includes a plurality of gas flow meters 2921, which are respectively arranged on a plurality of gas flow distribution delivery pipelines 292. The gas flow meters 2921 are located downstream of the corresponding gas flow control valves 260.

[0075] Before processing the wafer W, the target capacitance value of each gas flow control valve 260 can be obtained by the following method: adjusting the gas flow of each gas flow distribution pipeline 292, and observing multiple gas flow meters 2921 to know whether the gas flow ratio of multiple gas flow distribution pipelines 292 reaches the target gas flow ratio. If the target gas flow ratio is reached, the capacitance value detected by the capacitance detection device 230 at this time is used as the target capacitance value.

[0076] In this embodiment, the target capacitance value and the target gas flow rate ratio corresponding to each gas flow control valve 260 are also stored in the database of the controller 220. The controller 220 obtains the target capacitance value of each gas flow control valve 260 corresponding to the target gas flow rate ratio by querying the database, and adjusts the voltage applied to the corresponding driving device 263 according to the searched target capacitance value, so that the valve body opening of the gas flow control valve 260 reaches the target valve body opening.

[0077] If the valve body opening of each gas flow control valve 260 is adjusted based on the measurement results of multiple gas flow meters 2921 only through the PID (proportional-integral-differential) control method, it is easy to cause the gas flow ratio to respond slowly, and it is impossible to reach the target gas flow ratio within the preset time, and it is impossible to meet the process requirements. In addition, the valve body opening of each gas flow control valve 260 changes back and forth, which is also easy to cause multiple gas overshoots in the corresponding gas diversion delivery pipeline 292, thereby causing the air pressure in the reaction chamber 20 to oscillate. And the PID parameters (including the valve body opening) set by the PID method are only applicable to specific semiconductor processing machines. If the semiconductor processing machine uses incorrect PID parameters, the air pressure in the reaction chamber of the semiconductor machine is prone to steady-state oscillations and transient overshoots, and the robustness is very poor.

[0078] In the present invention, the target capacitance value is provided to the controller 220 by querying the database, which is equivalent to providing the preset valve body position to the controller 220. Not only is the control result of each valve body opening accurate, but it also takes very little time and has a fast gas flow rate ratio response speed. In addition, the gas delivery device of the present invention is not affected by the differences of the gas flow control valve 260, has low requirements for the selection of the gas flow control valve 260, and has good robustness.

[0079] In this embodiment, one of the multiple gas flow control valves 260 is always kept in a fully open state. In a preferred embodiment, the gas diversion delivery pipeline 292 where the fully open gas flow control valve 260 is located has the maximum target gas flow. By always keeping one gas flow control valve 260 fully open, the phenomenon of "holding" in the gas delivery device can be prevented. When the reaction gas is introduced into the reaction chamber 20, it is not easy to produce a sudden change in pressure in the reaction chamber 20, and the air pressure disturbance in the reaction chamber 20 is small, which can avoid the "impact" airflow in the reaction chamber 20 (which may cause the attachments on the reaction chamber wall or the surfaces of the components in the reaction chamber 20 to fall off, causing particulate contamination to the wafer W), effectively ensuring the yield rate of wafer W processing and the controllability of the process.

[0080] In this embodiment, the gas delivery device further includes a barometer 2911, which is disposed on the gas delivery main pipeline 291 and is used to measure the air pressure value in the gas delivery main pipeline 291. The barometer 2911 is also connected to the controller 220 via a signal, and when the measured air pressure value exceeds a set air pressure threshold (indicating that the gas delivery device has a "holding" phenomenon), the controller 220 generates an alarm message.

[0081] Due to the hysteresis effect of the piezoelectric ceramic material, after the gas flow control valve 260 reaches the target valve body opening, even if the driving voltage at this time is kept unchanged, the driving device 263 will continue to deform, thereby causing the valve body opening of the gas flow control valve 260 to deviate from the target valve body opening. In this embodiment, the moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment. The controller 220 is configured to adopt a proportional-integral-differential adjustment method, and from the first moment, the valve body opening of the gas flow control valve 260 is continuously controlled to achieve that the difference between the detected valve body opening and the target valve body opening is less than the preset difference threshold, and the gas flow control valve 260 reaches a steady state (the gas flow in the corresponding gas diversion delivery pipeline 292 no longer changes). The present invention effectively overcomes the problem of deviation between the actual valve body opening and the target valve body opening due to the hysteresis effect of the piezoelectric ceramic material.

[0082] This embodiment further provides a gas supply method, which is implemented using the gas delivery device as described in this embodiment, and includes the steps of: The position sensor detects the valve body opening of the corresponding gas flow control valve 260 in real time; The controller 220 adjusts the voltage applied to the corresponding drive device 263 based on the target gas flow ratio of multiple gas diversion delivery pipelines 292 and the valve body opening detected by the position sensor until the valve body opening detected by the position sensor reaches the target valve body opening that can achieve the target gas flow ratio.

[0083] In a preferred embodiment, one of the plurality of gas flow control valves 260 is always kept in a fully open state.

[0084] Further, the first valve body 261 or the second valve body 262 of the gas flow control valve 260 is electrically connected to the pulse power supply. The position sensor includes a capacitance detection device 230, and the capacitance detection device 230 detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed by the first valve body 261 and the second valve body 26. When the capacitance value detected by the capacitance detection device 230 reaches a preset target capacitance value, the controller 220 determines that the gas flow control valve 260 reaches the target valve body opening.

[0085] Further, the position sensor includes a first conductive element 231, a second conductive element 232 and a capacitance detection device 230. The first conductive element 231 or the second conductive element 232 is electrically connected to a pulse power supply. The first conductive element 231 passes through the first valve body 261 and is electrically insulated from the first valve body 261. The second conductive element 232 passes through the second valve body 262 and is electrically insulated from the second valve body 262, and the second conductive element 232 is arranged opposite to the first conductive element 231.

[0086] The capacitance detection device 230 detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed by the first conductive element 231 and the second conductive element 232. When the capacitance value detected by the capacitance detection device 230 reaches the preset target capacitance value, the controller 220 determines that the gas flow control valve 260 reaches the target valve body opening.

[0087] Furthermore, the database of the controller 220 stores: target gas flow ratios and target capacitance values ​​of each gas flow control valve 260 corresponding to the target gas flow ratios. The controller 220 obtains the target capacitance value by querying the database.

[0088] The moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment. Furthermore, the gas supply method further includes the steps of: Starting from the first moment, the controller 220 uses the proportional-integral-differential regulation method to continuously control the valve body opening of the gas flow control valve 260, so that the difference between the detected valve body opening and the target valve body opening is less than the preset difference threshold.

[0089] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0090] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A gas flow control valve, characterized in that: Include: A first valve body and a second valve body, wherein the first valve body and the second valve body are arranged opposite to each other and parallel to each other, and a gas flow channel for the reaction gas is formed therebetween; and a distance between the first valve body and the second valve body is defined as a valve body opening of the gas flow control valve; A driving device, which is made of piezoelectric ceramic and is used to drive the second valve body to move toward or away from the first valve body; the opening of the valve body is adjusted by adjusting the voltage applied to the driving device; A position sensor, used to detect the opening of the valve body; the position sensor includes a capacitance detection device; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body.

2. The gas flow control valve according to claim 1, characterized in that: The first valve body or the second valve body is electrically connected to a pulse power supply; the capacitance detection device detects the capacitance value by detecting the pulse width or voltage value of one of the first valve body and the second valve body that is not electrically connected to the pulse power supply.

3. The gas flow control valve according to claim 1, characterized in that: The position sensor further includes: a first conductive element and a second conductive element; The first conductive element or the second conductive element is electrically connected to a pulse power source; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

4. The gas flow control valve according to claim 3, characterized in that: The capacitance detection device detects the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element by detecting the pulse width or voltage value of one of the first conductive element and the second conductive element that is not electrically connected to the pulse power supply.

5. The gas flow control valve according to claim 2 or 4, characterized in that: The frequency of the pulse power supply is greater than or equal to 2KHZ.

6. The gas flow control valve according to claim 1, characterized in that: A sealing gasket is also included, which is arranged on a surface of the first valve body facing the second valve body, or on a surface of the second valve body facing the first valve body.

7. The gas flow control valve according to claim 6, characterized in that: The sealing pad is made of flexible insulating material.

8. A gas delivery device, characterized in that: include: A plurality of gas flow distribution pipelines are used to inject reaction gas into different areas in the reaction chamber; A plurality of gas flow control valves according to any one of claims 1 to 7, respectively arranged on a plurality of the gas diversion and delivery pipelines; the position sensor of the gas flow control valve comprises a capacitance detection device, and the capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body; The controller is configured to adjust the voltage applied to the corresponding drive device based on the target gas flow ratio of the multiple gas diversion and delivery pipelines and the valve body opening detected by the position sensor, until the valve body opening detected by the position sensor reaches a target valve body opening that can achieve the target gas flow ratio; when the capacitance value detected by the capacitance detection device reaches a preset target capacitance value, the controller determines that the gas flow control valve has reached the target valve body opening.

9. The gas delivery device according to claim 8, characterized in that: The position sensor further includes: a first conductive element and a second conductive element; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

10. The gas delivery device according to claim 8, characterized in that The database of the controller stores: the target gas flow ratio and the target capacitance value of each gas flow control valve corresponding to the target gas flow ratio; the controller obtains the target capacitance value by querying the database.

11. The gas delivery device according to claim 8, characterized in that One of the plurality of gas flow control valves is always kept in a fully open state.

12. The gas delivery device according to claim 11, characterized in that The gas flow distribution pipeline where the fully opened gas flow control valve is located has the maximum target gas flow.

13. The gas delivery device according to claim 8, characterized in that The moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment; the controller is configured to adopt a proportional-integral-differential adjustment method, and from the first moment on, continuously controls the valve body opening of the gas flow control valve to achieve that the difference between the detected valve body opening and the target valve body opening is less than a preset difference threshold.

14. The gas delivery device according to claim 8, characterized in that It also includes a plurality of gas flow meters, which are respectively arranged on the plurality of gas diversion and delivery pipelines; the gas flow meters are located downstream of the corresponding gas flow control valves.

15. The gas delivery device according to claim 8, characterized in that It also includes a barometer and a gas delivery main pipeline; the gas delivery main pipeline is connected between the reaction gas supply source and the multiple gas branch delivery pipelines; the barometer is arranged on the gas delivery main pipeline to measure the air pressure value in the gas delivery main pipeline.

16. The gas delivery device according to claim 15, characterized in that The barometer signal is connected to the controller, and when the air pressure value exceeds a set air pressure threshold, the controller generates an alarm message.

17. A gas supply method, implemented by using the gas delivery device according to any one of claims 8 to 16, characterized in that: Includes steps: The position sensor detects the valve body opening of the corresponding gas flow control valve in real time; the position sensor includes a capacitance detection device, and the capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first valve body and the second valve body; The controller adjusts the voltage applied to the corresponding drive device based on the target gas flow ratio of multiple gas diversion delivery pipelines and the valve body opening detected by the position sensor until the valve body opening detected by the position sensor reaches the target valve body opening that can achieve the target gas flow ratio; when the capacitance value detected by the capacitance detection device reaches a preset target capacitance value, the controller determines that the gas flow control valve has reached the target valve body opening.

18. The gas supply method according to claim 17, characterized in that: The position sensor further includes a first conductive element and a second conductive element; The first conductive element or the second conductive element is electrically connected to a pulse power source; The first conductive element passes through the first valve body and is electrically insulated from the first valve body; The second conductive element passes through the second valve body and is electrically insulated from the second valve body; the second conductive element is arranged opposite to the first conductive element; The capacitance detection device detects the valve body opening by detecting the capacitance value of the equivalent capacitance formed between the first conductive element and the second conductive element.

19. The gas supply method according to claim 17, characterized in that: The database of the controller stores: the target gas flow ratio and the target capacitance value of each gas flow control valve corresponding to the target gas flow ratio; the controller obtains the target capacitance value by querying the database.

20. The gas supply method according to claim 17, wherein: The moment when the valve body opening detected by the position sensor reaches the target valve body opening is recorded as the first moment, and the method further includes the steps of: Starting from the first moment, the controller adopts the proportional-integral-differential regulation method to continuously control the valve body opening of the gas flow control valve, so that the difference between the detected valve body opening and the target valve body opening is less than a preset difference threshold.

21. The gas supply method according to claim 17, characterized in that: One of the plurality of gas flow control valves is always kept in a fully open state.

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