Process chamber cleaning method and semiconductor process equipment

Abstract

The invention provides a method for cleaning a process chamber and semiconductor process equipment. The method comprises the following steps: cleaning the process chamber by using plasma; acquiring opening information of a flow regulating valve of an exhaust assembly used for vacuumizing the process chamber; and when the opening degree information meets the preset condition, cleaning is stopped. According to the method provided by the invention, the ending time of the cleaning process of the process chamber can be accurately judged in real time, and cleaning of the process chamber is stopped when the cleaning process of the process chamber reaches the ending point, so that insufficient cleaning or excessive cleaning of the process chamber is avoided.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a method for cleaning a process chamber and semiconductor process equipment. Background Art

[0002] During the semiconductor manufacturing process, while the film layer is deposited on the substrate, reaction byproducts are also formed on the sidewalls of the process chamber of the semiconductor process equipment. The reaction byproducts attached to the process chamber may crack or fall off during the process, which can easily cause the particle size in the film layer on the wafer to exceed the standard, affecting the product yield. Therefore, after the deposition process, the process chamber needs to be cleaned or maintained.

[0003] At present, fluorine-containing gases (e.g., CF4, C2F6, NF3) are usually introduced into the process chamber. The fluorine-containing gases can dissociate to form active fluorine free radicals (F * ), using the property that fluorine free radicals and reaction byproducts (e.g., SiO, SiN, SiON) deposited on the sidewalls of the process chamber can react chemically to generate gaseous silicon tetrafluoride (SiF4) to be discharged from the gas outlet of the process chamber to achieve the cleaning purpose. Among them, the timing of the end of cleaning is very important. If the cleaning is insufficient, it is easy to increase the particle size in the film layer. If the cleaning is excessive, the process chamber is easy to be damaged.

[0004] Therefore, how to provide a cleaning method that can accurately control the cleaning endpoint has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a method for cleaning a process chamber and a semiconductor process equipment.

[0006] In order to achieve the purpose of the present invention, a method for cleaning a process chamber is provided.

[0007] Methods include:

[0008] Using plasma to clean the process chamber;

[0009] Acquiring the opening information of the flow regulating valve of the exhaust assembly used for evacuating the process chamber;

[0010] When the opening information meets a preset condition, the cleaning is stopped.

[0011] In the cleaning method as described above, the opening information includes an opening value; and the preset condition includes the opening value gradually decreasing from a high point to a relatively stable value.

[0012] In the cleaning method as described above, the opening information includes an opening variation, and the step of obtaining the opening information of a flow regulating valve of an exhaust component for evacuating the process chamber includes:

[0013] Obtaining the opening value of the flow control valve at different times;

[0014] The first-order derivative of the opening value at each moment is calculated to obtain the opening variation of the flow control valve at different moments.

[0015] In the cleaning method as described above, the preset condition includes that after a predetermined period of time, the absolute value of the opening degree change is less than a first preset threshold.

[0016] The cleaning method as described above, wherein the opening information also includes the second-order derivative of the opening value;

[0017] After obtaining the opening variation of the flow control valve at different times, the method further includes:

[0018] The opening change at each moment is derived to obtain the second-order derivative of the opening value of the flow control valve at different moments.

[0019] The cleaning method as described above, wherein the preset condition includes that the absolute value of the second-order derivative of the opening value is less than a second preset threshold value; or

[0020] The preset condition includes: the absolute value of the opening change at multiple consecutive moments is less than a first preset threshold and the absolute value of the second-order derivative of the opening value at multiple consecutive moments is less than a second preset threshold.

[0021] The cleaning method as described above, wherein, before calculating the first-order derivative of the opening value at each moment, further comprises: filtering the opening value of the flow control valve;

[0022] After obtaining the opening variation of the flow control valve at different times, the method further includes: filtering the opening variation of the flow control valve.

[0023] The cleaning method as described above, wherein the opening value of the flow control valve is filtered according to the following relationship;

[0024] Y n =aX n +bY n-1 ; Among them, X n The flow control valve is at t n The opening value at the moment, Y n-1 The flow control valve is at t n-1 The opening filter value at the moment, Y n The flow control valve is at tn The opening filter value at the moment; a and b are both constants.

[0025] The cleaning method as described above, wherein the process chamber is cleaned by plasma, specifically comprising:

[0026] Plasma is introduced into the process chamber, and the process chamber is cleaned by using the plasma.

[0027] As another technical solution, an embodiment of the present invention further provides a semiconductor process equipment, including:

[0028] Process chamber;

[0029] An exhaust component, connected to the process chamber to evacuate the process chamber, the exhaust component comprising a flow regulating valve;

[0030] The controller includes at least one processor and at least one memory, wherein the memory stores a computer program, and when the process chamber is cleaned by plasma, the processor executes the computer program to perform the following steps:

[0031] Acquiring the opening information of the flow regulating valve of the exhaust component;

[0032] When the opening information meets a preset condition, the cleaning is stopped.

[0033] The present invention has the following beneficial effects:

[0034] In the technical solution of the process chamber cleaning method provided by the embodiment of the present invention, by obtaining the opening information of the flow control valve, and when the opening information meets the preset conditions, it is determined that the cleaning process of the process chamber has reached the cleaning end point, and the cleaning of the process chamber is stopped. In this way, not only can the end time of the cleaning of the process chamber be controlled in real time and accurately, but it can also be achieved by using the existing components of the semiconductor process equipment, without the need to improve the structure of the semiconductor process equipment or add new components.

[0035] The semiconductor process equipment provided by the embodiment of the present invention can control the cleaning endpoint of the cleaning process of the process chamber in real time and accurately by executing the cleaning method of the process chamber provided by the embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of a cleaning method for a process chamber provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of a process flow of a cleaning method for a process chamber provided in an embodiment of the present application;

[0038] Figure 3 is a curve diagram showing the content of SiF4 in the process chamber and the corresponding cleaning time during the process chamber cleaning process;

[0039] Figure 4 A curve diagram showing the opening value and the corresponding cleaning time during the process chamber cleaning process;

[0040] Figure 5 It is a curve diagram between the opening change amount and the corresponding cleaning time during the process chamber cleaning process;

[0041] Figure 6 A curve diagram showing the second-order derivative of the opening value during the process chamber cleaning process and the corresponding cleaning time;

[0042] Figure 7 A schematic flow chart of another method for cleaning a process chamber provided in an embodiment of the present application;

[0043] Figure 8 A schematic diagram of the structure of a semiconductor process equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the technical solution of the present invention, the cleaning method of the process chamber and the semiconductor process equipment provided by the present invention are described in detail below with reference to the accompanying drawings.

[0045] Before introducing the embodiments of the present application, the technical background of the embodiments of the present application is first explained: At present, the commonly used methods for cleaning the process chamber are in-situ plasma cleaning and remote plasma (remote plasma source, RPS) cleaning. Taking in-situ plasma cleaning as an example, the cleaning principle is: fluorine-based gases such as CF4 or C2F6 and oxygen are introduced into the process chamber, and the fluorine-based gas is dissociated by the radio frequency system to produce active F* and ions with a certain energy. The active F* reacts chemically with the reaction byproduct SiO of the side wall of the process chamber according to the following formula (1), and reacts chemically with the reaction byproduct SiN of the side wall of the process chamber according to the following formula (2), and obtains gaseous SiF4. In this way, the cleaning of the side wall of the process chamber is achieved.

[0046] F*+SiO→SiF4↑+O Formula (I)

[0047] F*+SiN→SiF4↑+N Formula (II)

[0048] In order to achieve an appropriate cleaning degree of the process chamber, technicians in this field usually tend to think of inferring the time required for a process chamber to complete a cleaning based on existing data and experience, and designing the cleaning time and frequency as a constant. However, due to other factors, the thickness of the reaction byproducts formed on the process chamber often varies. Therefore, using a fixed cleaning time and frequency to clean the process chamber may still result in insufficient cleaning or excessive cleaning.

[0049] As the cleaning process proceeds, the content of gaseous SiF4 in the process chamber will change. When the cleaning reaches the end point, the chemical reaction approaches to stop, and the content of gaseous SiF4 remains basically unchanged. Therefore, the related art discloses a process chamber provided with a concentration detection member and a controller. The concentration detection member can detect the content of SiF4 in the process chamber. The controller determines whether the chemical reaction of the active F* and the reaction byproducts of the side wall of the process chamber tends to stop based on the SiF4 content detected by the concentration detection member, so as to determine whether the cleaning end time is reached. In this way, accurate control of the cleaning end time is achieved. For example, the concentration detection member may include an infrared emitter and an infrared detector.

[0050] Furthermore, the process chamber disclosed in the related art determines the end time of cleaning by detecting the content of SiF4, and the semiconductor process equipment needs to be additionally provided with structures such as concentration detection components, which makes the structure of the semiconductor process equipment complicated.

[0051] To this end, the inventor of the present application has come up with the idea of ​​using the state of a component already in the semiconductor process equipment as the basis for determining the end point of cleaning, and the state of the component changes with the cleaning process of the process chamber. Based on this concept, the present application embodiment provides a cleaning method for a process chamber and a semiconductor process equipment, which determines whether the cleaning process of the process chamber has reached the end point of cleaning based on the opening information of the flow control valve of the exhaust component used to evacuate the process chamber, and controls the cleaning to stop when the cleaning process reaches the end point.

[0052] Figure 1 A schematic diagram of a cleaning method for a process chamber provided in an embodiment of the present application. Figure 1 The semiconductor process equipment 100 includes a process chamber 110, a remote plasma device 120, an exhaust component 130 and a pressure control system. A base 111 is arranged in the process chamber 110. The base 111 is used to place the wafer to be processed. The process chamber 110 can be used to perform deposition process, etching process and other processing processes on the wafer. The process chamber 110 has an air inlet and an air outlet.

[0053] The remote plasma device 120 includes a remote plasma system 121, which is connected to the gas inlet through an inlet pipe 123. The gas source 122 disposed outside the process chamber 110 is used to provide a cleaning gas (such as CF4, C2F6) to the remote plasma system 121. The remote plasma system 121 ionizes the cleaning gas to generate plasma using a radio frequency system, and the plasma is transported to the process chamber 110 through the inlet pipe 123. It should be understood by those skilled in the art that this embodiment only takes remote plasma cleaning as an example to illustrate the present invention, and the present invention is not limited thereto, and in-situ plasma cleaning of the process chamber can also be performed.

[0054] The exhaust assembly 130 includes an outlet pipe 132, one end of which is connected to the outlet of the process chamber 110, and the other end is connected to an exhaust pump 131 disposed outside the process chamber 110, and the exhaust pump 131 is used to evacuate the process chamber 110. The exhaust assembly 130 also includes a flow regulating valve 140, which is disposed on the outlet pipe 132.

[0055] The pressure control system includes a connected pressure detection device 150 and a pressure controller 160. The pressure detection device 150 is used to detect the air pressure in the process chamber 110. The pressure controller 160 controls the flow control valve 140 according to the air pressure value detected by the pressure detection device 150 to adjust the opening of the flow control valve, thereby achieving the purpose of maintaining a constant air pressure in the process chamber 110.

[0056] It is understandable that when the wafer is processed in the process chamber 110, in addition to the reaction byproducts formed on the side walls of the process chamber, the reaction byproducts are also deposited on the flow control valve 140. Among them, the flow control valve 140 includes a valve body and a valve plate, and the valve plate can move relative to the valve body so that the flow control valve is opened and closed to conduct the gas outlet pipeline or cut off the gas outlet pipeline. It should be understood that the reaction byproducts accumulated on the flow control valve 140 will affect the gap between the valve body and the valve plate, and then affect the opening of the flow control valve 140. Specifically, compared with the flow control valve 140 without the accumulation of reaction byproducts, under the premise that the valve plate moves the same distance, the flow control valve 140 with the accumulation of reaction byproducts allows a smaller amount of gas to pass through per unit time.

[0057] During the cleaning process of the process chamber, the reaction byproducts accumulated on the flow control valve 140 will also react with the plasma to achieve the cleaning of the flow control valve 140. Therefore, the opening of the flow control valve 140 will change with the cleaning process of the process chamber. Specifically, the cleaning process of the process chamber can be divided into the initial stage, the middle stage and the final stage.

[0058] In the early stage of the process chamber cleaning process, the amount of plasma gas introduced into the process chamber 110 by the remote plasma device increases, the active F* participating in the chemical reaction increases, the SiF4 content generated increases sharply, and the gas pressure in the process chamber 110 increases sharply. In addition, in the early stage, there are many reaction by-products accumulated on the flow control valve 140, and the gap between the valve body and the valve plate is mostly blocked by the reaction by-products. In general, in the early stage of the process chamber cleaning process, while the amount of gas in the process chamber 110 increases, the gap between the valve body and the valve plate is smaller. Therefore, in order to maintain a constant gas pressure in the process chamber 110, the pressure controller 160 controls the flow control valve 140 to increase the opening.

[0059] In the middle of the process chamber cleaning process, the reaction byproducts on the side wall of the process chamber 110 and the flow control valve 140 are gradually cleaned, the amount of gas introduced into the process chamber 110 by the remote plasma device gradually decreases, the active F* participating in the chemical reaction gradually decreases, the SiF4 content generated decreases, and the gas pressure in the process chamber 110 decreases accordingly. In addition, in the middle period, the reaction byproducts accumulated on the flow control valve 140 gradually decrease, and the part of the gap between the valve body and the valve plate blocked by the reaction byproducts is relatively small. In general, in the middle of the process chamber cleaning process, while the amount of gas in the process chamber 110 decreases, the gap between the valve body and the valve plate increases. Therefore, in order to maintain a constant gas pressure in the process chamber 110, the pressure controller 160 controls the flow control valve 140 to reduce the opening.

[0060] At the end of the process chamber cleaning process, the reaction byproducts on the side wall of the process chamber 110 are cleaned up, the chemical reaction is close to stopping, the amount of gas introduced into the process chamber 110 by the remote plasma device is stable, the SiF4 content no longer changes, and the gas pressure in the process chamber 110 tends to be constant. In addition, at the end, the reaction byproducts accumulated on the flow control valve 140 are cleaned up, and the gap between the valve body and the valve plate is not blocked by the reaction byproducts. In general, at the end of the process chamber cleaning process, the amount of gas in the process chamber 110 tends to be stable, and there are no reaction byproducts blocking the gap between the valve body and the valve plate. Therefore, the pressure controller 160 controls the opening of the flow control valve 140 to remain constant.

[0061] Based on the above application scenario architecture, the embodiment of the present application provides a method for cleaning a process chamber. It should be understood that the execution subject of the cleaning method can be a semiconductor process equipment, or an electronic device capable of controlling the semiconductor process equipment, such as a server.

[0062] Figure 2 A schematic diagram of a process chamber cleaning method provided in an embodiment of the present application. Figure 2 The present application discloses a method for cleaning a process chamber, which mainly includes the following steps:

[0063] S101, cleaning the process chamber using plasma.

[0064] S102, obtaining the opening information of the flow regulating valve of the exhaust assembly used for evacuating the process chamber.

[0065] The flow control valve is not limited to a butterfly valve, and may also be a flow valve such as a stop valve or a gate valve.

[0066] S103, when the opening information meets the preset conditions, stop cleaning.

[0067] According to the above description, when plasma is used to clean the process chamber, the amount of plasma gas in the process chamber and the content of SiF4 produced by the chemical reaction are positively correlated with the amount of gas in the process chamber, and the amount of gas in the process chamber and the amount of reaction byproducts accumulated on the flow control valve are positively correlated with the opening value of the flow control valve. When the cleaning process of the process chamber reaches the end point, the chemical reaction stops, the amount of gas in the process chamber tends to a constant value, and there are no reaction byproducts blocking the gap between the valve body and the valve plate, and the opening value of the flow control valve remains basically unchanged.

[0068] It can be seen that the opening information of the flow control valve changes with the cleaning process of the process chamber, and at the end of the cleaning process of the process chamber, the opening value of the flow control valve remains constant. In this way, in step S103, the opening information meets the preset conditions, which indicates that the cleaning process of the process chamber has reached the end point, so the cleaning of the process chamber can be stopped.

[0069] Based on the cleaning method of the process chamber provided in this embodiment, it is possible to determine in real time and accurately whether the cleaning process of the process chamber has reached the end point. When it is determined that the cleaning process of the process chamber has ended, the cleaning of the process chamber is stopped to avoid over-cleaning or under-cleaning of the process chamber.

[0070] Moreover, the method provided in this embodiment is implemented based on a flow regulating valve and a pressure control system. Since the flow regulating valve and the pressure control system are existing components of semiconductor process equipment, this can avoid the phenomenon that the semiconductor process equipment becomes more complex and the cost increases due to structural improvements or the addition of new components.

[0071] It can be understood that, depending on the different meanings of the opening information, the preset conditions are also different accordingly.

[0072] In some embodiments, the opening information refers to the opening value of the flow control valve. In this embodiment, the preset condition may be: the opening value gradually decreases from a high point to a relatively stable value. That is to say, at multiple consecutive moments including the current moment, the opening values ​​of the flow control valve are all relatively low and substantially equal, that is, the opening value of the flow control valve remains unchanged at multiple consecutive moments. According to the above description, this means that the cleaning process of the process chamber has reached the end point, and the cleaning of the process chamber can be stopped.

[0073] The opening value of the flow control valve specifically refers to the relative opening (unit: ‰), that is, the ratio of the flow rate allowed to pass through the flow control valve at a certain opening to the flow rate allowed to pass through when fully open. Among them, the opening value of the flow control valve can be specifically acquired by the acquisition module. Exemplarily, the acquisition module can be an opening meter. Alternatively, in other embodiments, the acquisition module can also be an angle sensor arranged on the valve plate of the flow control valve or an encoder arranged on the motor shaft that drives the valve plate to rotate, and the encoder is used to collect the angular displacement of the valve plate, and the angular displacement of the valve plate can be converted into the opening value of the flow control valve.

[0074] In some embodiments, the opening information may include an opening variation, wherein the opening variation may be expressed as a first-order derivative of a curve of the opening value of the flow control valve changing with time, to reflect the speed at which the opening value of the flow control valve changes with time.

[0075] At this time, the specific execution process of the above step S102 may include the following steps.

[0076] S1021, obtaining the opening value of the flow control valve at different times.

[0077] S1022, calculating the first-order derivative of the opening value at each moment to obtain the opening variation of the flow control valve at different moments.

[0078] In one example, the method for calculating the first-order derivative of the opening value at each moment in S1022 may be: arranging the opening values ​​corresponding to the flow control valve at each moment to form multiple groups of data (t1, X1), (t2, X2), (t3, X3), ..., X n The flow control valve is at t n The opening value corresponding to the moment, fitting multiple groups of data can get the curve of the opening value changing with time, and the opening function can be established according to the curve of the opening value changing with time. The first-order derivative can be obtained by taking the first-order derivative of the opening function, and the value of the first-order derivative at a certain moment (i.e., the first-order derivative value) is the change in the opening of the flow control valve at that moment.

[0079] In another example, since the first-order derivative of the opening value at a certain moment means the rate of change of the opening value near that moment, the opening change amount can also be obtained by determining the rate of change of the opening value near each moment. At this time, the above S1022 can specifically determine the opening change amount at different moments according to the following formula (III). Here, X in formula (III) n ′ is the flow control valve at t n The opening change at a certain moment, where n is a positive integer.

[0080]

[0081] In this way, since the opening value is obtained in real time during the cleaning process of the process chamber, when the cleaning process of the process chamber has not reached the end, the accuracy of determining the opening change amount based on the change rate of the opening value near each time is higher.

[0082] As a further optional example, the opening value of the flow control valve can be obtained at set time intervals. n -t n-1 =Δt, Δt is a positive constant. Schematically, Δt can be set to 0.2s, that is, the opening value of the flow control valve is obtained every 0.2s. This is conducive to further simplifying the amount of calculation of the opening change.

[0083] In this embodiment, the preset condition may be: after a preset time, the absolute value of the opening change is less than the first preset threshold. Step S103 is: when after a preset time, the absolute value of the opening change of the flow control valve is less than the first preset threshold, stop cleaning the process chamber.

[0084] It should be understood that the predetermined time length is unlimited, for example, it can be 5s, 10s, etc. By reasonably designing the predetermined time length, the opening value of the flow control valve is at the falling edge, and the absolute value of the opening change is less than the first preset threshold value, and then the cleaning is stopped. In this way, it is helpful to avoid the misjudgment of the end point of the cleaning process caused by the first-order derivative of the opening value being 0 when the opening value of the flow control valve reaches the peak value and the opening change is also less than the first preset threshold value.

[0085] Among them, the first preset threshold is a positive number close to 0, which can be specifically designed based on experience and actual working conditions. For example, the first preset threshold can be 0.0002, 0.0004, 0.0006, 0.0008, 0.001. Compared with setting the preset condition that the opening change is equal to 0, the benefit of this design in this embodiment is that the opening change is relaxed to within the preset range to meet the preset condition. If the first preset threshold is set to 0.001, the preset range is [-0.001, 0.001]. In this way, the opening change is allowed to have a reasonable error, which helps to reduce the acquisition accuracy requirements for the acquisition module.

[0086] According to the above description, the content of SiF4 is positively correlated with the opening value of the flow control valve. Here, when cleaning the process chamber, the opening value of the flow control valve during the cleaning process is detected and recorded, and at the same time, the cleaning method of this embodiment is simulated to determine the opening value and opening change of the flow control valve at different times during the cleaning process. At the same time, the content of SiF4 in the process chamber during the cleaning process is recorded, and the effectiveness of the cleaning method provided by this embodiment is verified by judging whether the content of SiF4 is positively correlated with the opening value of the flow control valve. The content of SiF4, the opening value and the opening change in the above process chamber are fitted with the corresponding time to form a curve, and it can be obtained Figure 3 , Figure 4 and Figure 5 .in, Figure 3 is a curve diagram of the content of SiF4 in the process chamber and the corresponding cleaning time during the process chamber cleaning process. Figure 4 It is a curve diagram between the opening value and the corresponding cleaning time during the process chamber cleaning process. Figure 5 It is a curve diagram between the opening change amount and the corresponding cleaning time during the process chamber cleaning process. The cleaning time corresponding to a certain moment is the time interval between the moment and the start time of cleaning the process chamber.

[0087] Depend on Figure 5 It can be seen that the opening change of the flow control valve when the cleaning time is up to 90s is 0, which means that the opening value of the flow control valve does not change substantially at this moment, meeting the preset conditions of this embodiment; Figure 3 and Figure 4 At this time, the content of SiF4 in the process chamber and the opening value of the flow control valve tend to be constant, and the cleaning process is close to the end, so the cleaning of the process chamber can be stopped. It can be understood that, combined with the curve fitted by the data obtained by simulating the cleaning process of the process chamber, it can be verified that the cleaning method provided by this embodiment can accurately control the timing of the end of cleaning of the process chamber.

[0088] On the basis of the technical solution that the opening information includes the opening variation, the opening information may further include the second derivative of the opening value. The second derivative of the opening value may be expressed as the second derivative of the curve according to the change of the opening value over time, and also as the first derivative of the curve according to the change of the opening variation over time. Therefore, in this embodiment, after step S1022, step S102 further includes step S1023.

[0089] S1023, taking the derivative of the opening change at each moment to obtain the second-order derivative of the opening value of the flow control valve at different moments.

[0090] In one example, the method for deriving the opening change at each moment in S1023 can be: arranging the opening change corresponding to the flow control valve at each moment to form multiple sets of data, fitting these multiple sets of data to obtain a curve of the opening change over time, and establishing an opening change function based on the curve of the opening change over time, and taking the first-order derivative of the opening change function to obtain the second-order derivative of the opening value.

[0091] In another example, the second-order derivative is the rate of change of the first-order derivative. The first-order derivative of the opening change at a certain moment means the rate of change of the opening change near that moment. Therefore, the second-order derivative of the opening value can also be obtained by determining the rate of change of the opening change near each moment. At this time, the above step S1023 can specifically determine the second-order derivative of the opening value at different moments according to the following formula (IV). Here, X in formula (IV) n ″ is the flow control valve at t n The second derivative of the opening value at time.

[0092]

[0093] In this way, since the opening value is obtained in real time during the cleaning process of the process chamber, when the cleaning process of the process chamber has not reached the end, the second-order derivative of the opening value determined according to the change rate of the opening change at each time is more accurate.

[0094] In the embodiment where the opening information includes the opening change amount and the opening change rate, the preset condition in the above step S103 includes multiple possible implementation methods.

[0095] In the first possible implementation, the preset condition is that the absolute value of the second-order derivative of the opening value is less than the second preset threshold. At this time, step S103 is specifically: when the absolute value of the second-order derivative of the opening value of the flow control valve is less than the second preset threshold, stop cleaning the process chamber.

[0096] Similar to the first preset threshold, the second preset threshold is also a positive number close to 0. Moreover, the second preset threshold may be the same as or different from the first preset threshold. For example, the second preset threshold may be 0.001, 0.002, 0.003, 0.004, or 0.005. Compared with setting the preset condition that the opening change rate is equal to 0, the benefit of this design of the present embodiment is that the second-order derivative of the opening value is relaxed to within the set range, that is, the preset condition is met. If the second preset threshold is 0.005, the set range is [-0.005, 0.005]. In this way, the second-order derivative of the opening value allows reasonable errors, which helps to reduce the requirements for acquisition accuracy.

[0097] The cleaning method of the process chamber of the present embodiment can be determined by simulating Figure 5The second-order derivative of the opening value at each moment in the process of chamber cleaning is shown, and it is fitted with the corresponding moment to form a curve, which can be obtained Figure 6 .in, Figure 6 It is a curve diagram between the second-order derivative of the opening value during the process chamber cleaning process and the corresponding cleaning time.

[0098] Depend on Figure 6 It can be seen that the second-order derivative of the opening value of the flow control valve when the cleaning time is up to 100s is 0, which meets the preset conditions of this embodiment; Figure 3 and Figure 4 At this time, the content of SiF4 in the process chamber and the opening value of the flow control valve tend to be constant, and the cleaning process is close to the end, so the cleaning of the process chamber can be stopped. It can be understood that, combined with the curve fitted by the data obtained by simulating the cleaning process of the process chamber, it can be verified that the cleaning method provided by this embodiment can accurately control the timing of the end of cleaning of the process chamber.

[0099] In a second possible implementation, the preset condition is: the absolute value of the opening change at multiple consecutive moments is less than the first preset threshold value and the absolute value of the second-order derivative of the opening value at multiple consecutive moments is less than the second preset threshold value. In this case, step S103 is specifically: when the absolute value of the opening change of the flow control valve at multiple consecutive moments is less than the first preset threshold value, and the absolute value of the second-order derivative of the opening value of the flow control valve at multiple consecutive moments is less than the second preset threshold value, the cleaning is stopped.

[0100] It should be noted that when the preset condition is only that the absolute value of the opening change is less than the first preset threshold, please refer to Figure 5 , when the cleaning time is T1, the opening change of the flow control valve is 0, which meets the preset conditions; combined with Figure 3 and Figure 4 At this time, the SiF4 content in the process chamber and the opening value of the flow control valve are both at the maximum value, and the cleaning process of the process chamber has not reached the end time. When the preset condition is only that the absolute value of the second derivative of the opening value is less than the second preset threshold, please refer to Figure 6 , when the cleaning time is T2, the second-order derivative of the opening value is 0, which meets the preset conditions; combined with Figure 3 , Figure 4 and Figure 5 At this time, the content of SiF4 in the process chamber and the opening value of the flow control valve rise sharply, and the change in the opening value of the flow control valve is close to the maximum value. The cleaning process of the process chamber is in the early stage and has not reached the end.

[0101] It can be seen that when the preset condition is only that the absolute value of the opening change is less than the first preset threshold, or when the preset condition is only that the absolute value of the second-order derivative of the opening value is less than the second preset threshold, there is a possibility of misjudgment of the end time of cleaning the process chamber. The preset conditions of this embodiment have the preset conditions of the above two possible implementation methods, which is conducive to avoiding misjudgment of the cleaning endpoint and further improving the accuracy of judging the end time of cleaning the process chamber.

[0102] It is worth noting that by setting the preset conditions that the absolute value of the opening change at multiple consecutive moments is less than the first preset threshold value, and the absolute value of the second-order derivative of the opening value is less than the second preset threshold value, on the one hand, it is necessary to judge the opening change and the second-order derivative of the opening value at multiple moments, which increases the number of judgments and helps to improve the accuracy of the judgment. On the other hand, by judging the opening change or the opening change rate at multiple consecutive moments including the current moment, it is possible to avoid misjudgment of the cleaning endpoint, greatly improving the accuracy of controlling the timing of the cleaning end of the process chamber.

[0103] As an optional implementation, before step S1022, step S1024 may be performed first.

[0104] S1024, filtering the opening value of the flow control valve.

[0105] That is to say, the opening value of the flow control valve is first filtered, and then the first-order derivative of the filtered opening value is calculated to obtain the opening change of the flow control valve at different times. In this way, the influence of random interference that may exist in the acquisition process on the opening value can be effectively reduced, which is conducive to improving the calculation accuracy of the opening change.

[0106] Specifically, the opening value of the flow control valve can be filtered according to the following formula (5). Here, X in formula (5) n The flow control valve is at t n The opening value at the moment, Y n-1 The flow control valve is at t n-1 The opening filter value corresponding to the moment, Y n The flow control valve is at t n The opening filter value at the moment, a and b are both constants. The sum of a and b can be 1.

[0107] Y n =aX n +bY n-1 =aX n +(1-a)Y n-1 Formula (V)

[0108] Based on this, a comparison table of the opening values ​​of the flow control valve at different times and the corresponding opening filter values ​​at the times can be obtained, as shown in Table 1.

[0109] Table 1

[0110] time Opening value Opening filter value <![CDATA[t1]]> <![CDATA[X1]]> <![CDATA[Y1=X1]]> <![CDATA[t2]]> <![CDATA[X2]]> <![CDATA[Y2=aX2+(1-a)Y1]]> <![CDATA[t3]]> <![CDATA[X3]]> <![CDATA[Y3=aX3+(1-a)Y2]]> …… …… …… <![CDATA[t n ]]> <![CDATA[X n ]]> <![CDATA[Y n =aX n +(1-a)Y n-1 ]]>

[0111] It can be seen from Table 1 that the opening filter value corresponding to the flow control valve at the starting time is the opening value corresponding to that time.

[0112] It is worth pointing out that the value of a can be designed based on experience and actual working conditions. The smaller the value of a is, the better the filtering effect is. For example, the value of a can be selected as 0.1.

[0113] According to the above description, based on this embodiment, the opening change in step S1022 can be determined according to the following formula (VI), where Y n ′ is the flow control valve at t n The change in opening at each moment.

[0114]

[0115] Of course, in other embodiments of the present application, other filtering models may be used to filter the opening value, and this embodiment does not limit this. In contrast, the method provided in this embodiment uses formula (V) for filtering, which reduces the amount of calculation and minimizes the change of the collected opening value.

[0116] Similarly, before the opening variation is derived, the opening variation may be filtered. Specifically, as an optional implementation, after step S1022 and before step S1023, step S1025 may be further performed.

[0117] S1025, filtering the opening change of the flow control valve.

[0118] In this way, the method of this embodiment first filters the opening variation, and then takes the derivative of the filtered opening variation to obtain the second-order derivative of the opening value of the flow control valve at different times. In this way, the influence of random interference that may exist in the acquisition process on the second-order derivative of the opening value can be further reduced, and the calculation accuracy of the second-order derivative of the opening value can be improved.

[0119] There are many ways to filter the opening change, for example, it can be similar to the filtering method of the opening value. Specifically, the opening change of the flow control valve can be filtered according to the following formula (VII). Here, Z in formula (VII) n ′ is the flow control valve at t nThe filter value of the change amount at the moment, c and d are both constants. The sum of c and d can be 1.

[0120] Z n ′=cY n ′+dZ n-1 ′=cY n ′+(1-c)Z n-1 ′ Formula (VII)

[0121] Based on this, a comparison table of the opening variation of the flow control valve at different times and the corresponding variation filter value at the time can be obtained, as shown in Table 2.

[0122] Table 2

[0123] time Opening change Change filter value <![CDATA[t1]]> <![CDATA[Y1′]]> <![CDATA[Z1′=Y1′]]> <![CDATA[t2]]> <![CDATA[Y2′]]> <![CDATA[Z2=cY2′+(1-c)Z1′]]> <![CDATA[t3]]> <![CDATA[Y3′]]> <![CDATA[Z3=cY3′+(1-c)Z2′]]> …… …… …… <![CDATA[t n ]]> <![CDATA[Y n ′]]> <![CDATA[Z n =cY n +(1-c)Z n-1 ′]]>

[0124] It can be seen from Table 2 that the change amount filter value corresponding to the flow control valve at the starting moment is the opening change amount corresponding to that moment.

[0125] It is worth pointing out that the value of c can be designed based on experience and actual working conditions. The smaller the value of c is, the better the filtering effect is. For example, the value of c can be selected as 0.05.

[0126] According to the above description, based on this embodiment, the second-order derivative of the opening value in step S1023 can be determined according to the following formula (eight), where Y n ″ is the flow control valve at t n The second derivative of the opening value at time.

[0127]

[0128] In any of the above embodiments, the implementation of step S101 is different depending on whether the cleaning method of the process chamber is in-situ plasma cleaning or remote plasma cleaning. Taking the remote plasma cleaning method as an example, in step S101, plasma is introduced into the process chamber through a remote plasma device, and the plasma can react with the side walls of the process chamber and the reaction byproducts accumulated on the flow control valve, so that the reaction byproducts are removed, thereby achieving cleaning. At this time, the method of stopping cleaning in step S103 is to shut down the remote plasma system.

[0129] Figure 7 A schematic diagram of another process chamber cleaning method provided in an embodiment of the present application. Figure 7 In a specific example, the cleaning method includes:

[0130] S201, introducing plasma into the process chamber.

[0131] S202, in the process of introducing plasma into the process chamber to clean the process chamber, collecting the opening values ​​of the flow control valve at different times.

[0132] S203, filtering the opening value of the flow control valve.

[0133] S204, calculating the first-order derivative of the opening value after filtering at each moment to obtain the opening variation of the flow control valve at different moments.

[0134] S205, filtering the opening variation of the flow control valve.

[0135] S206, taking the derivative of the opening variation after filtering at each moment to obtain the second-order derivative of the opening value of the flow control valve at different moments.

[0136] S207, determine whether the absolute value of the opening change at multiple consecutive moments is less than a first preset threshold; if so, execute S208; if not, return to S204.

[0137] S208, determining whether the absolute value of the second-order derivative of the opening value at a plurality of consecutive moments is less than a second preset threshold; if so, executing S209; if not, returning to S204.

[0138] Step S209: stop introducing plasma into the process chamber.

[0139] Figure 8 This is a schematic diagram of the structure of a semiconductor process equipment provided by an embodiment of the present application. Figure 8 An embodiment of the present application further provides a semiconductor process equipment, which includes: a process chamber, an exhaust component and a controller 200.

[0140] The exhaust component is connected to the process chamber to evacuate the process chamber, and the exhaust component includes a flow regulating valve.

[0141] The controller 200 includes at least one processor 202 and at least one memory 201. The memory 201 is used to store a computer program. The processor 202 is used to execute the computer program to perform the following steps when cleaning the process chamber using plasma, to obtain the opening information of the flow regulating valve of the exhaust component; when the opening information meets the preset condition, the cleaning is stopped.

[0142] The controller 200 may further include an input / output interface 203. The input / output interface 203 may include an independent output interface and an input interface, or may be an integrated interface integrating input and output, wherein the output interface is used to output data, and the input interface is used to obtain input data.

[0143] In some embodiments, the processor 202 is specifically configured to, when the opening information includes an opening value, stop cleaning when the opening value gradually decreases from a high point to a relatively stable value.

[0144] In some embodiments, the processor 202 is specifically used to obtain the opening value of the flow control valve at different times when the opening information includes the opening change; and calculate the first-order derivative of the opening value at each time to obtain the opening change of the flow control valve at different times.

[0145] In some embodiments, the processor 202 is specifically configured to stop cleaning when the absolute value of the opening change is less than a first preset threshold after a predetermined period of time.

[0146] In some embodiments, the processor 202 is specifically used to, when the opening information also includes the second-order derivative of the opening value, after obtaining the opening change of the flow control valve at different times, take the derivative of the opening change at each time to obtain the second-order derivative of the opening value of the flow control valve at different times.

[0147] In some embodiments, the processor 202 is specifically used to stop cleaning when the absolute value of the second-order derivative of the opening value is less than a second preset threshold; or, stop cleaning when the absolute value of the opening change at multiple consecutive moments is less than the first preset threshold and the absolute value of the second-order derivative of the opening value at multiple consecutive moments is less than the second preset threshold.

[0148] In some embodiments, the processor 202 is specifically used to filter the opening value of the flow control valve before calculating the first-order derivative of the opening value at each moment; after obtaining the opening change of the flow control valve at different moments, filter the opening change of the flow control valve.

[0149] In some embodiments, the processor 202 is specifically used to introduce plasma into the process chamber to clean the process chamber using the plasma. In this embodiment, the semiconductor process equipment also includes a remote plasma device, which is used to generate plasma and introduce plasma into the process chamber to clean the process chamber.

[0150] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles 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 considered to be within the scope of protection of the present invention.

Claims

1. A method for cleaning a process chamber, characterized in that: include: Using plasma to clean the process chamber; Acquiring the opening information of the flow regulating valve of the exhaust assembly used for evacuating the process chamber; When the opening information meets a preset condition, the cleaning is stopped.

2. The cleaning method according to claim 1, characterized in that: The opening information includes an opening value; The preset condition includes that the opening value gradually decreases from a high point to a relatively stable value.

3. The cleaning method according to claim 1, characterized in that: The opening information includes an opening variation, and the obtaining of the opening information of a flow regulating valve of an exhaust component for evacuating the process chamber includes: Obtaining the opening value of the flow control valve at different times; The first-order derivative of the opening value at each moment is calculated to obtain the opening variation of the flow control valve at different moments.

4. The cleaning method according to claim 3, characterized in that: The preset condition includes that after a predetermined period of time, the absolute value of the opening degree change is less than a first preset threshold.

5. The cleaning method according to claim 3, characterized in that: The opening information also includes the second-order derivative of the opening value; After obtaining the opening variation of the flow control valve at different times, the method further includes: The opening change at each moment is derived to obtain the second-order derivative of the opening value of the flow control valve at different moments.

6. The cleaning method according to claim 5, characterized in that: The preset condition includes that the absolute value of the second-order derivative of the opening value is less than a second preset threshold; or The preset condition includes: the absolute value of the opening change at multiple consecutive moments is less than a first preset threshold and the absolute value of the second-order derivative of the opening value at multiple consecutive moments is less than a second preset threshold.

7. The cleaning method according to any one of claims 3 to 6, characterized in that: Before taking the first-order derivative of the opening value at each moment, the method further includes: Performing filtering processing on the opening value of the flow control valve; After obtaining the opening variation of the flow control valve at different times, the method further includes: The opening variation of the flow control valve is filtered.

8. The cleaning method according to claim 7, characterized in that: The opening value of the flow control valve is filtered according to the following relationship; Y n =aX n +bY n-1 ; Among them, X n The flow control valve is at t n The opening value at the moment, Y n-1 The flow control valve is at t n-1 The opening filter value at the moment, Y n The flow control valve is at t n The opening filter value at the moment; a and b are both constants.

9. The cleaning method according to any one of claims 1 to 6, characterized in that: The method of cleaning the process chamber by using plasma specifically includes: Plasma is introduced into the process chamber, and the process chamber is cleaned by using the plasma.

10. A semiconductor process equipment, characterized in that: include: Process chamber; An exhaust component, connected to the process chamber to evacuate the process chamber, the exhaust component comprising a flow regulating valve; The controller includes at least one processor and at least one memory, wherein the memory stores a computer program, and when the process chamber is cleaned by plasma, the processor executes the computer program to perform the following steps: The opening information of the flow regulating valve of the exhaust component is obtained; when the opening information meets a preset condition, the cleaning is stopped.

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