Cleaning method for process chamber and semiconductor process device

Abstract

The present application provides a cleaning method for a process chamber and a semiconductor process device. The method comprises: using plasma to clean a process chamber; acquiring information about the degree of opening of a flow regulating valve of a gas evacuation assembly used for vacuumizing the process chamber; and when the information about the degree of opening meets a preset condition, stopping cleaning. By means of the method provided by the present application, the timing for ending a process chamber cleaning process can be accurately determined in real time, and cleaning of the process chamber is stopped when the end point of the process chamber cleaning process is reached, thereby avoiding insufficient cleaning or excessive cleaning of the process chamber.

Description

Process chamber cleaning method and semiconductor process equipment Technical Field

[0001] The present application 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, as film layers are deposited on substrates, reaction byproducts also form on the sidewalls of the process chambers of semiconductor processing equipment. These byproducts can crack or break off during the process, potentially causing excessive particle size in the film layers on the wafers and affecting product yield. Therefore, after the deposition process, the process chambers must be cleaned or maintained.

[0003] Currently, fluorine-containing gases (e.g., CF4, C2F6, NF3) are usually introduced into the process chamber. Fluorine-containing gases can dissociate to form active fluorine free radicals (F * ) utilizes the chemical reaction between fluorine radicals and reaction byproducts deposited on the process chamber sidewalls (e.g., SiO, SiN, SiON) to generate gaseous silicon tetrafluoride (SiF4), which is then discharged from the process chamber's gas outlet to achieve cleaning purposes. Controlling the timing of the cleaning completion is crucial. Insufficient cleaning can easily lead to increased particle size within the film layer, while excessive cleaning can easily damage the process chamber.

[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.

[0005] Summary of the Invention

[0006] The present application aims to solve at least one of the technical problems existing in the prior art, and proposes a process chamber cleaning method and semiconductor process equipment, which can solve the technical problem in the prior art that the cleaning endpoint cannot be accurately controlled.

[0007] To achieve the purpose of this application, a method for cleaning a process chamber is provided, the cleaning method comprising:

[0008] Using plasma to clean the process chamber;

[0009] Acquiring opening information of a flow regulating valve of an exhaust assembly used to evacuate 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 the opening value of the flow control valve; and the preset condition includes the opening value gradually decreasing from a high point to a relatively stable value.

[0012] In the cleaning method described above, wherein the opening information includes an opening variation, obtaining the opening information of a flow control valve of an exhaust assembly 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 further includes the second 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 variation 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 derivative of the opening value is less than a second preset threshold; or

[0020] The preset conditions include: 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 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 moments, the method further includes: performing filtering processing on 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 nThe flow control valve is at t n 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 using plasma, specifically comprises:

[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 application further provides a semiconductor process equipment, including:

[0028] process chamber;

[0029] an exhaust component, connected to the process chamber for evacuating 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. When the process chamber is cleaned using plasma, the processor executes the computer program to perform the following steps:

[0031] Obtaining the opening information of the flow control valve of the exhaust component;

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

[0033] This application has the following beneficial effects:

[0034] In the technical solution for the process chamber cleaning method provided in the embodiments of this application, by obtaining information about the opening of a flow control valve and, when the opening information meets a preset condition, determining that the process chamber cleaning process has reached the end point, the process chamber cleaning process is stopped. This not only enables real-time and accurate control of the end point of the process chamber cleaning, but also utilizes existing components of semiconductor process equipment, eliminating the need to modify the structure of the semiconductor process equipment or add new components.

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

[0036] FIG1 is a schematic diagram of a method for cleaning a process chamber provided in an embodiment of the present application;

[0037] FIG2 is a schematic flow chart of a method for cleaning a process chamber provided in an embodiment of the present application;

[0038] FIG3 is a graph showing the relationship between the SiF4 content in the process chamber and the corresponding cleaning time during the process chamber cleaning process;

[0039] FIG4 is a graph showing the relationship between the opening value and the corresponding cleaning time during the process chamber cleaning process;

[0040] FIG5 is a graph showing the relationship between the change in opening degree and the corresponding cleaning time during the process chamber cleaning process;

[0041] FIG6 is a graph showing the relationship between the second derivative of the opening value and the corresponding cleaning time during the process chamber cleaning process;

[0042] FIG7 is a schematic flow chart of another method for cleaning a process chamber provided in an embodiment of the present application;

[0043] FIG8 is a schematic structural diagram 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 application, the cleaning method of the process chamber and the semiconductor process equipment provided by the present application 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: Currently, the commonly used methods for cleaning process chambers are in situ plasma cleaning and 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 gases are dissociated by the radio frequency system to produce active F * and ions with a certain energy, active F * The reaction byproduct SiO reacts with the sidewall of the process chamber according to the following formula (1), and the reaction byproduct SiN reacts with the sidewall of the process chamber according to the following formula (2), thereby obtaining gaseous SiF4. In this way, the sidewall of the process chamber is cleaned. * +SiO→SiF4↑+O Formula (1) F * +SiN→SiF4↑+N Formula (2)

[0046] To achieve an appropriate cleaning level for a process chamber, those skilled in the art typically infer the time required to complete a cleaning cycle based on existing data and experience, and then design the cleaning duration and frequency as constants. However, due to other factors, the thickness of reaction byproducts formed on the process chamber often varies. Therefore, using a fixed cleaning duration and frequency for cleaning a process chamber may still result in under-cleaning or over-cleaning.

[0047] As the cleaning process progresses, 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 equipped with a concentration detection element and a controller. The concentration detection element can detect the content of SiF4 in the process chamber, and the controller determines the active F4 content based on the SiF4 content detected by the concentration detection element. * The end of cleaning can be determined by determining whether the chemical reaction of the byproducts with the process chamber sidewalls has ceased. This allows for precise control of the end of cleaning. For example, the concentration detection component can include an infrared emitter and an infrared detector.

[0048] 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.

[0049] To this end, the inventors of this application have devised a method for determining the endpoint of cleaning based on the status of existing components in semiconductor process equipment, which changes as the process chamber is cleaned. Based on this concept, embodiments of this application provide a process chamber cleaning method and semiconductor process equipment that determines whether the cleaning process has reached its endpoint based on the opening information of a flow control valve in an exhaust assembly used to evacuate the process chamber, and controls the cleaning process to stop when the cleaning process reaches its endpoint.

[0050] FIG1 is a schematic diagram illustrating a process chamber cleaning method according to an embodiment of the present application. Referring to FIG1 , semiconductor process equipment 100 includes a process chamber 110, a remote plasma device 120, an exhaust assembly 130, and a pressure control system. A pedestal 111 is disposed within process chamber 110 for placing wafers to be processed. Process chamber 110 can be used to perform deposition, etching, and other processing on the wafers. Process chamber 110 has an air inlet and an air outlet.

[0051] The remote plasma device 120 includes a remote plasma system 121, which is connected to the gas inlet via an inlet pipe 123. A gas source 122 disposed outside the process chamber 110 is used to provide a cleaning gas (e.g., CF4, C2F6) to the remote plasma system 121. The remote plasma system 121 uses a radio frequency system to ionize the cleaning gas to generate plasma, which is then transported into the process chamber 110 via the inlet pipe 123. It should be understood by those skilled in the art that this embodiment merely uses remote plasma cleaning as an example to illustrate the present application, and the present application is not limited thereto. In-situ plasma cleaning of the process chamber may also be performed.

[0052] The exhaust assembly 130 includes an outlet pipe 132. One end of the outlet pipe 132 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. The exhaust pump 131 is used to evacuate the process chamber 110. The exhaust assembly 130 also includes a flow control valve 140 disposed on the outlet pipe 132.

[0053] 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.

[0054] It is understandable that when the wafer is processed in the process chamber 110, in addition to the reaction by-products formed on the side walls of the process chamber, the reaction by-products are also deposited on the flow regulating valve 140. Among them, the flow regulating 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 regulating valve is opened and closed to connect the gas outlet line or cut off the gas outlet line. It should be understood that the reaction by-products accumulated on the flow regulating valve 140 will affect the gap between the valve body and the valve plate, and then affect the opening of the flow regulating valve 140. Specifically, compared with the flow regulating valve 140 without the accumulation of reaction by-products, under the premise that the valve plate moves the same distance, the flow regulating valve 140 with the accumulation of reaction by-products allows a smaller amount of gas to pass through per unit time.

[0055] During the process chamber cleaning process, reaction byproducts accumulated on the flow control valve 140 also react with the plasma to clean the flow control valve 140. Therefore, the opening of the flow control valve 140 changes as the process chamber cleaning progresses. Specifically, the process chamber cleaning process can be divided into the initial, middle, and final stages.

[0056] 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, and the active F * As the amount of SiF4 increases, the amount of SiF4 generated increases dramatically, causing the pressure in process chamber 110 to rise sharply. Furthermore, in the initial stages, a large amount of reaction byproducts accumulates on flow control valve 140, obstructing a significant portion of the gap between the valve body and the valve plate. Generally speaking, in the initial stages of the process chamber cleaning process, as the amount of gas in process chamber 110 increases, the gap between the valve body and the valve plate decreases. Therefore, to maintain a constant pressure in process chamber 110, pressure controller 160 increases the opening of flow control valve 140.

[0057] In the middle of the process chamber cleaning process, the reaction byproducts on the sidewall of the process chamber 110 and the flow control valve 140 are gradually cleaned, and the amount of plasma gas introduced into the process chamber 110 by the remote plasma device is gradually reduced, and the active F * As the amount of SiF4 produced decreases, the pressure in process chamber 110 decreases accordingly. Furthermore, during the middle stage of the process chamber cleaning process, the accumulation of reaction byproducts on flow control valve 140 gradually decreases, and the portion of the gap between the valve body and valve plate blocked by reaction byproducts becomes relatively small. In general, during the middle stage of the process chamber cleaning process, the amount of gas in process chamber 110 decreases while the gap between the valve body and valve plate increases. Therefore, to maintain a constant pressure in process chamber 110, pressure controller 160 reduces the opening of flow control valve 140.

[0058] At the end of the process chamber cleaning process, the reaction byproducts on the sidewalls of process chamber 110 are cleaned, the chemical reaction is nearly stopped, the amount of plasma gas introduced into process chamber 110 by the remote plasma device stabilizes, the SiF4 content no longer changes, and the gas pressure in process chamber 110 becomes constant. Furthermore, at the end of the process chamber cleaning process, the reaction byproducts accumulated on flow control valve 140 are cleaned, and the gap between the valve body and valve plate is no longer blocked by reaction byproducts. In general, at the end of the process chamber cleaning process, the gas volume in process chamber 110 stabilizes, and reaction byproducts no longer block the gap between the valve body and valve plate. Therefore, pressure controller 160 maintains a constant opening of flow control valve 140.

[0059] Based on the above application scenario architecture, the present embodiment provides a process chamber cleaning method. It should be understood that the execution subject of the cleaning method can be semiconductor process equipment or an electronic device capable of controlling semiconductor process equipment, such as a server.

[0060] FIG2 is a flow chart of a method for cleaning a process chamber provided in an embodiment of the present application. Referring to FIG2 , an embodiment of the present application discloses a method for cleaning a process chamber, which mainly includes the following steps:

[0061] S101, cleaning the process chamber using plasma.

[0062] S102 , obtaining opening information of a flow regulating valve of an exhaust assembly used for evacuating a process chamber.

[0063] 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.

[0064] S103, when the opening information meets the preset conditions, stop cleaning.

[0065] As described above, when plasma cleaning a process chamber, the amount of plasma gas in the process chamber and the amount of SiF4 produced by the chemical reaction are positively correlated with the amount of gas in the process chamber. The amount of gas in the process chamber and the amount of reaction byproducts accumulated on the flow control valve are also positively correlated with the valve opening. At the end of the process chamber cleaning process, the chemical reaction ceases, the gas volume in the process chamber approaches a constant value, and with no reaction byproducts blocking the gap between the valve body and the valve plate, the flow control valve opening remains essentially unchanged.

[0066] Thus, the flow control valve's opening information changes as the process chamber is cleaned, and at the end of the process chamber cleaning process, the flow control valve's opening value remains constant. Thus, in step S103, the fact that the opening information meets the preset conditions indicates that the process chamber cleaning process has reached its end point, and therefore, cleaning of the process chamber can be stopped.

[0067] Based on the process chamber cleaning method provided in this embodiment, it is possible to determine in real time and accurately whether the cleaning process of the process chamber has reached its 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.

[0068] 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 of semiconductor process equipment becoming more complex and increasing costs due to structural improvements or the addition of new components.

[0069] It can be understood that, depending on the different meanings of the opening information, the preset conditions are also different accordingly.

[0070] In some embodiments, the opening information refers to the opening value of the flow control valve. In this embodiment, the preset condition can specifically be: the opening value gradually decreases from a high point to a relatively stable value. In other words, the high point is a relatively high value. The relatively stable value means that at multiple consecutive moments including the current moment, the opening value of the flow control valve is a relatively low value and is substantially equal. In other words, the opening value of the flow control valve remains unchanged at multiple consecutive moments. According to the content described above, this means that the cleaning process of the process chamber has reached the end point, and cleaning of the process chamber can be stopped.

[0071] 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 an acquisition module. Exemplarily, the acquisition module can be an opening meter. Alternatively, in other embodiments, the acquisition module can also be an angle sensor provided on the valve plate of the flow control valve or an encoder provided on the motor shaft that drives the valve plate to rotate. The encoder is used to acquire 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.

[0072] In some embodiments, the opening information may include an opening variation, which may be expressed as a first-order derivative of a curve showing the opening value of the flow control valve changing with time, and is used to reflect how quickly the opening value of the flow control valve changes with time.

[0073] At this time, the specific execution process of the above step S102 may include the following steps.

[0074] S1021, obtaining the opening value of the flow control valve at different times.

[0075] 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.

[0076] In one example, the method for calculating the first-order derivative of the opening value at each moment in step S1022 can be: arranging the opening values ​​corresponding to the flow control valve at n moments to form multiple groups of data (t1, X1), (t2, X2), (t3, X3), ..., (t n , X n ), where n is a positive integer, X n The flow control valve is at t n The opening value corresponding to the moment, fitting multiple groups of data can obtain 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 opening change of the flow control valve at that moment.

[0077] In another example, since the first-order derivative of the opening value corresponding to a certain moment is 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. In this case, the above step S1022 can specifically determine the opening change amount at different moments according to the following formula (3). Here, X in formula (3) n ' is the flow control valve at t n The change in opening at a certain moment, where n is a positive integer.

[0078] In this way, since the opening value is obtained in real time during the process chamber cleaning process, when the process chamber cleaning process has not reached the end, the accuracy of determining the opening change amount based on the change rate of the opening value near each moment is higher.

[0079] 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, where Δt is a constant and positive value. For example, Δt can be set to 0.2s, meaning the flow control valve opening value is obtained every 0.2s. This helps further reduce the amount of computation required to calculate the opening change.

[0080] In this embodiment, the preset condition may specifically be: after a predetermined time period, the absolute value of the opening change is less than a first preset threshold. Step S103 specifically includes: after a predetermined time period, when the absolute value of the opening change of the flow control valve is less than the first preset threshold, stopping cleaning the process chamber.

[0081] It should be understood that this application does not limit the predetermined duration; for example, it can be 5 seconds, 10 seconds, etc. By properly designing the predetermined duration, the flow control valve opening is on a declining edge, i.e., gradually decreasing, and cleaning is stopped when the absolute value of the change in opening is less than a first preset threshold. This helps avoid misjudging the end point of the cleaning process when the flow control valve opening reaches its peak value, the first-order derivative of the opening value is zero, and the change in opening is also less than the first preset threshold.

[0082] The first preset threshold is a positive number close to 0 and 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, or 0.001. Compared with setting the preset condition as the opening change equal to 0, the benefit of this design in this embodiment is that the preset condition can be satisfied by relaxing the opening change to within the preset range. If the first preset threshold is set to 0.001, the preset range is [-0.001, +0.001]. In this way, a reasonable error is allowed in the opening change, which helps to reduce the acquisition accuracy requirements of the acquisition module.

[0083] 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. 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. By determining whether the content of SiF4 is positively correlated with the opening value of the flow control valve, the effectiveness of the cleaning method provided by this embodiment is verified. The content of SiF4 in the process chamber, the opening value, and the opening change are respectively fitted to the corresponding time to form a curve, and Figures 3, 4, and 5 can be obtained. Among them, Figure 3 is a curve diagram of the content of SiF4 in the process chamber during the cleaning process and the corresponding cleaning time, Figure 4 is a curve diagram of the opening value during the cleaning process and the corresponding cleaning time, and Figure 5 is a curve diagram of the opening change during the cleaning process and the corresponding cleaning time. The cleaning time corresponding to a certain time is the time interval between that time and the start time of cleaning the process chamber.

[0084] As can be seen in Figure 5, the change in the flow control valve's opening during the 90-second cleaning period is zero, meaning the flow control valve's opening remains essentially unchanged at that point, satisfying the pre-set conditions of this embodiment. Combined with Figures 3 and 4, the SiF4 content and the flow control valve's opening within the process chamber are now constant, indicating the cleaning process is nearing completion, and cleaning of the process chamber can be discontinued. This demonstrates that the curve fitted with the data from the simulated process chamber cleaning process verifies that the cleaning method provided by this embodiment can accurately control the timing of the process chamber cleaning completion.

[0085] Based on the technical solution in which the opening information includes the opening change, the opening information can further include the second derivative of the opening value. The second derivative of the opening value can be expressed as the second derivative of a curve showing the opening value changing over time, or as the first derivative of a curve showing the opening change changing over time. Therefore, in this embodiment, after step S1022, step S102 also includes step S1023.

[0086] S1023, deriving the difference in opening value at each moment to obtain the second-order derivative of the opening value of the flow control valve at different moments.

[0087] In one example, the method for deriving the opening change at each moment in step 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.

[0088] 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. In this case, 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) is n " is the flow control valve at t n The second derivative of the opening value at time.

[0089] In this way, since the opening value is obtained in real time during the process chamber cleaning process, when the process chamber cleaning process has not reached the end, the second-order derivative of the opening value determined based on the change rate of the opening change at each time is more accurate.

[0090] 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 implementations.

[0091] In a first possible implementation, the preset condition is that the absolute value of the second derivative of the opening value is less than a second preset threshold. In this case, step S103 specifically includes: when the absolute value of the second derivative of the opening value of the flow control valve is less than the second preset threshold, stopping cleaning the process chamber.

[0092] 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 setting range is [-0.005, +0.005]. In this way, the second-order derivative of the opening value allows for reasonable errors, which helps to reduce the requirements for acquisition accuracy.

[0093] By simulating the process chamber cleaning method of this embodiment, the second-order derivative of the aperture value at each moment during the process chamber cleaning process shown in FIG5 can be determined. This second-order derivative is then fitted to the corresponding moment to form a curve, resulting in FIG6 . FIG6 is a graph showing the second-order derivative of the aperture value during the process chamber cleaning process versus the corresponding cleaning time.

[0094] As can be seen from Figure 6, the second-order derivative of the flow control valve's opening value corresponding to the 100-second cleaning duration is 0, meeting the pre-set conditions of this embodiment. Combined with Figures 3 and 4, at this point, the SiF4 content in the process chamber and the flow control valve's opening value tend to be constant, indicating that the cleaning process is nearing completion, and cleaning of the process chamber can be stopped. It can be understood that, combined with the curve fitted with the data obtained from the simulated process chamber cleaning process, it can be verified that the cleaning method provided by this embodiment can accurately control the timing of the end of the process chamber cleaning.

[0095] In a second possible implementation, the preset condition is that 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. In this case, step S103 specifically includes stopping cleaning when the absolute value of the opening change of the flow control valve at multiple consecutive moments is less than the first preset threshold, 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.

[0096] It should be noted that when the preset condition is only that the absolute value of the change in the opening is less than the first preset threshold, refer to Figure 5. When the cleaning time is T1, the change in the opening of the flow control valve is 0, which meets the preset condition. In conjunction with Figures 3 and 4, at this time, the SiF4 content in the process chamber and the opening of the flow control valve are both at their maximum values, and the cleaning process of the process chamber has not yet reached its end. When the preset condition is only that the absolute value of the second derivative of the opening is less than the second preset threshold, refer to Figure 6. When the cleaning time is T2, the second derivative of the opening is 0, which meets the preset condition. In conjunction with Figures 3, 4, and 5, at this time, the SiF4 content in the process chamber and the opening of the flow control valve increase sharply, and the change in the opening of the flow control valve is close to its maximum value. The cleaning process of the process chamber is in its early stages and has not yet reached its end.

[0097] As can be seen, if the preset condition is solely that the absolute value of the opening change is less than the first preset threshold, or if the preset condition is solely that the absolute value of the second derivative of the opening value is less than the second preset threshold, there is a possibility of misjudging the end point of cleaning the process chamber. However, the preset conditions of this embodiment combine the preset conditions of both possible implementations, which helps avoid misjudgments of the cleaning endpoint and further improves the accuracy of determining the end point of cleaning the process chamber.

[0098] It's worth noting that by setting the preset conditions of the absolute value of the aperture change at multiple consecutive moments being less than a first preset threshold and the absolute value of the second derivative of the aperture value being less than a second preset threshold, the system eliminates the need to determine the aperture change and the second derivative at multiple moments, increasing the number of determinations and improving accuracy. Furthermore, by determining the aperture change or rate of change at multiple consecutive moments, including the current moment, misjudgment of the cleaning endpoint is avoided, significantly improving the accuracy of controlling the end point of the process chamber cleaning.

[0099] As an optional implementation, before step S1022, step S1024 may be performed first.

[0100] S1024: Filter the opening value of the flow control valve.

[0101] In other words, the flow control valve opening value is first filtered, and then the first-order derivative of the filtered opening value is taken to obtain the opening change of the flow control valve at different times. This can effectively reduce the impact of random interference that may exist during the acquisition process on the opening value, which is conducive to improving the accuracy of the calculation of the opening change.

[0102] Specifically, the opening value of the flow control valve can be filtered according to the following 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. n =aX n +bY n-1 =aX n +(1-a)Y n-1 Formula (5)

[0103] 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 each time can be obtained, as shown in Table 1.

[0104] Table 1

[0105] It can be seen from Table 1 that the opening filter value corresponding to the flow control valve at each moment is the opening value corresponding to each moment.

[0106] It is worth noting that the value of a can be designed based on experience and actual working conditions. The smaller the value of a, the better the filtering effect. For example, the value of a can be selected as 0.1.

[0107] According to the above description, based on this embodiment, the opening change in step S1022 can be determined according to the following formula (6), where Y n ' is the flow control valve at t n The change in opening at each moment.

[0108] 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 (5) for filtering, which reduces the amount of computation and minimizes changes to the acquired opening value.

[0109] 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.

[0110] S1025: Filter the opening variation of the flow control valve.

[0111] With this design, 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. This further reduces the impact of random interference that may exist during the acquisition process on the second-order derivative of the opening value, thereby improving the calculation accuracy of the second-order derivative of the opening value.

[0112] 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 n The filter value of the change at the moment, c and d are both constants. The sum of c and d can be 1. n '=cY n '+dZ n-1 '=cY n '+(1-c)Z n-1 Formula (VII)

[0113] 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.

[0114] Table 2

[0115] It can be seen from Table 2 that the filter value of the change amount corresponding to the flow control valve at each moment is the change amount of the opening corresponding to each moment.

[0116] It is worth noting that the value of c can be designed based on experience and actual working conditions. The smaller the value of c, the better the filtering effect. For example, the value of c can be selected as 0.05.

[0117] According to the above description, based on this embodiment, the second derivative of the opening value in step S1023 can be determined according to the following formula (8), where Y n " is the flow control valve at t n The second derivative of the opening value at time.

[0118] In any of the above embodiments, the implementation of step S101 varies depending on whether the process chamber is cleaned using in-situ plasma cleaning or remote plasma cleaning. Taking remote plasma cleaning as an example, in step S101, plasma is introduced into the process chamber via a remote plasma device. The plasma reacts with reaction byproducts accumulated on the sidewalls of the process chamber and the flow control valve, removing the reaction byproducts and achieving cleaning. In this case, the method for stopping cleaning in step S103 is to shut down the remote plasma system.

[0119] FIG7 is a flow chart of another method for cleaning a process chamber provided in an embodiment of the present application. Referring to FIG7 , in a specific example, the cleaning method includes:

[0120] S201, introducing plasma into the process chamber.

[0121] S202 , while plasma is introduced into the process chamber to clean the process chamber, the opening values ​​of the flow regulating valve at different times are collected.

[0122] S203: Filter the opening value of the flow control valve.

[0123] S204 , calculating the first-order derivative of the filtered opening value at each moment to obtain the opening variation of the flow control valve at different moments.

[0124] S205: Filter the opening variation of the flow control valve.

[0125] 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.

[0126] S207, determining whether the absolute value of the opening change at a plurality of consecutive moments is less than a first preset threshold; if so, executing S208; if not, returning to S204.

[0127] 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.

[0128] Step S209: stop supplying plasma into the process chamber.

[0129] FIG8 is a schematic structural diagram of a semiconductor process equipment provided in an embodiment of the present application. Referring to FIG8 , an embodiment of the present application further provides a semiconductor process equipment, the semiconductor process equipment comprising: a process chamber, an exhaust assembly, and a controller 200 .

[0130] The exhaust component is connected to the process chamber to evacuate the process chamber, and the exhaust component includes a flow regulating valve.

[0131] Controller 200 includes at least one processor 202 and at least one memory 201. Memory 201 is configured to store a computer program. Processor 202, when plasma cleaning a process chamber, is configured to execute the computer program to perform the following steps: obtain information about the opening of a flow control valve of an exhaust assembly; and terminate cleaning when the opening information meets a preset condition.

[0132] 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. The output interface is used to output data, and the input interface is used to obtain input data.

[0133] In some embodiments, the processor 202 is specifically configured to, when the opening information includes the opening value of the flow control valve, stop cleaning when the opening value gradually decreases from a high point to a relatively stable value.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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 to 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.

[0138] 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.

[0139] In some embodiments, the processor 202 is specifically configured to introduce plasma into the process chamber to clean the process chamber using the plasma. In this embodiment, the semiconductor process equipment further includes a remote plasma device configured to generate plasma and introduce the plasma into the process chamber to clean the process chamber.

[0140] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present application, and such modifications and improvements are also considered to be within the scope of protection of the present application.

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 the opening value of the flow control valve; 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 assembly is connected to the process chamber to evacuate the process chamber. The gas assembly includes 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: Acquiring the opening information of the flow regulating valve of the exhaust component; When the opening information meets a preset condition, the cleaning is stopped.

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