Vacuum threshold determination method, apparatus, equipment, medium, and product

Abstract

The present invention provides a method, apparatus, equipment, medium, and product for determining a vacuum threshold that improves the measurement throughput of a transport chamber. [Solution] The vacuum threshold determination method includes loading a target wafer into the transport chamber of a charged particle beam imaging apparatus, performing a vacuuming operation on the transport chamber, obtaining the vacuum level of the transport chamber at multiple points in time during the vacuuming operation, and searching for a target first vacuum curve that matches the vacuum levels at multiple points in time from each first vacuum curve in a database. The database includes multiple first vacuum curves and corresponding vacuum stability values, each first vacuum curve used to represent the trend of change in vacuum level after loading wafers with different outgassing amounts into the transport chamber. The method also includes determining the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold for the transport chamber corresponding to the target wafer.

Description

Technical Field

[0001] This application relates to the technical field of electron beam measurement, and particularly to a method, apparatus, device, medium, and product for determining a vacuum threshold value.

Background Art

[0002] In current electron beam measurement devices, the transfer chamber functions as a transition region between the atmosphere and the vacuum state. Before performing electron beam measurement on a wafer, first, the wafer is evacuated to a preset vacuum threshold value in the transfer chamber, and then the transfer valve is opened to transfer the wafer into the main vacuum chamber to avoid large vacuum fluctuations in the main vacuum chamber.

[0003] In the conventional method, first, after switching the machine platform to the corresponding mode, the transfer chamber is evacuated to the preset vacuum threshold value in that mode, and then the evacuation valve of the transfer chamber is turned off to stop evacuating the transfer chamber. After waiting for a certain period of time, if the vacuum degree of the transfer chamber is not less than the preset vacuum threshold value, the wafer is transferred to the main chamber.

[0004] However, if the vacuum degree of the transfer chamber is less than the preset vacuum threshold value after a certain period of time, it means that the wafer itself is releasing gas. The accuracy of the preset vacuum threshold value is not high, and it is necessary to continue evacuating the transfer chamber. Thus, due to the low accuracy of setting the vacuum threshold value of the transfer chamber, the evacuation time is significantly extended, and the measurement throughput of the transfer chamber decreases.

Summary of the Invention

[0005] Embodiments of this application provide a method, apparatus, device, medium, and product for determining a vacuum threshold value that can improve the measurement throughput of a transfer chamber.

[0006] One embodiment of the present invention provides a method for determining a vacuum threshold, the vacuum threshold determination method is After loading the target wafer into the transport chamber of the charged particle beam imaging apparatus, a vacuum operation is performed on the transport chamber. To obtain the vacuum level of the transport chamber at multiple points in time during the vacuuming operation, The database searches for a target first vacuum curve that matches the vacuum level at multiple time points from each first vacuum curve. The database contains multiple first vacuum curves and corresponding vacuum level stability values, and each first vacuum curve is used to represent the trend of change in vacuum level after wafers with different outgassing amounts are loaded into the transport chamber. This includes determining the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer.

[0007] One embodiment of the present invention provides a vacuum threshold determination device, the vacuum threshold determination device is A transport chamber vacuuming module that, after loading a target wafer into the transport chamber of a charged particle beam imaging apparatus, performs a vacuuming operation on the transport chamber, A vacuum level acquisition module that acquires the vacuum level of the transport chamber at multiple points in time during the vacuuming operation, A target first vacuum level curve that matches the vacuum level at multiple time points is searched from each first vacuum level curve in the database. The database contains multiple first vacuum level curves and corresponding vacuum level stability values. Each first vacuum level curve is used as a curve matching module to represent the trend of change in vacuum level after wafers with different outgassing amounts are loaded into the transport chamber. The system includes a threshold determination module that determines a vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer.

[0008] According to one embodiment of the present invention, an electronic device is provided that includes a memory and a program or instruction stored in the memory and executable by a processor, wherein when the program or instruction is executed by the processor, an electronic device is provided that implements a vacuum threshold determination method provided in any one embodiment of the present invention.

[0009] According to one embodiment of the present invention, a readable storage medium in which a program or instruction is stored is provided, and when the program or instruction is executed by a processor, a vacuum threshold determination method according to any embodiment of the present invention is realized.

[0010] According to one embodiment of the present invention, a computer program product is provided, and when a command in the computer program product is executed by the processor of an electronic device, the electronic device is made to execute a vacuum threshold determination method according to any embodiment of the present invention.

[0011] In the vacuum threshold determination method according to the embodiment of the present invention, a database is pre-set in which a corresponding first vacuum curve and a vacuum stability value corresponding to the first vacuum curve are stored after wafers with different outgassing amounts are loaded into the transport chamber. Then, the vacuum at multiple points in time during the process of performing the vacuuming operation of the transport chamber where the target wafer is located is compared with each first vacuum curve in the database to obtain a target first vacuum curve corresponding to the target wafer. This makes it possible to determine the outgassing amount type corresponding to the target wafer and accurately obtain the vacuum threshold of the transport chamber where the target wafer is located. In this way, the embodiment of the present invention accurately determines the vacuum threshold of the transport chamber where the target wafer is located using a target first vacuum curve that matches the target wafer. This avoids the problem of a significant extension of the vacuuming time due to inaccurate setting of the vacuum threshold and improves the measurement throughput of the transport chamber. [Brief explanation of the drawing]

[0012] To more clearly explain the technology of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described below, and those skilled in the art will be able to obtain other drawings based on these drawings without requiring any creative effort. [Figure 1] This is a schematic flowchart of a vacuum threshold determination method according to one embodiment of the present invention. [Figure 2] This is a schematic diagram of the standard pressure curve of a transport chamber in which a target wafer is located according to one embodiment of the present invention. [Figure 3] This is a schematic diagram of the structure of a vacuum threshold determination device according to one embodiment of the present invention. [Figure 4] A schematic diagram of the structure of a vacuum threshold determination device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] The features and exemplary embodiments of each aspect of the present application will be described in detail below, and the present application will be described in further detail below with reference to the drawings and specific examples in order to further clarify the purpose, technology and advantages of the present application. The specific examples described herein are for interpretation purposes only and do not limit the present application. Those skilled in the art will be able to implement the present application without requiring some of these specific details. The following description of the embodiments is intended to help the present application be better understood by illustrating examples of the present application.

[0014] In this specification, relational terms such as "First" and "Second" are used to distinguish one entity or operation from another, and do not necessarily require or imply the existence of any actual relationship or order between these entities or operations. Furthermore, the terms "equipment," "includes," or any other variants are intended to cover non-exclusive inclusion, thereby including not only those elements but also other elements not explicitly listed, or further elements specific to such process, method, article, or apparatus. Unless further restrictions are imposed, an element limited by the phrase "equipment" does not preclude the existence of other identical elements in a process, method, article, or apparatus that equips that element.

[0015] Furthermore, the acquisition, storage, use, and processing of data in the technology of this application all comply with the relevant provisions of laws and regulations.

[0016] In the embodiments of this application, some existing industry technologies, such as software, components, and models, may be referenced. These should be considered illustrative examples, intended to illustrate the feasibility of implementing the technologies of this application, and not to imply that the applicant has already or necessarily used such technologies.

[0017] In the conventional method, the machine is first switched to the corresponding mode, the transport chamber is evacuated to a preset vacuum threshold in that mode, and then the vacuum valve of the transport chamber is turned off to stop the vacuuming of the transport chamber. After waiting for a certain period of time, if the vacuum level of the transport chamber is not lower than the preset vacuum threshold, the wafer is transported to the main chamber. However, because the accuracy of setting the vacuum threshold of the transport chamber in this method is not high, the vacuuming time is significantly extended, and the measurement throughput of the transport chamber decreases.

[0018] This application aims to provide a method, apparatus, device, medium, and product for determining a vacuum threshold value. In the method for determining a vacuum threshold value according to an embodiment of this application, after wafers with different outgassing amounts are loaded into a transfer chamber, a database storing a corresponding first vacuum curve and a vacuum stability value corresponding to the first vacuum curve is preset. Then, during the process of performing a vacuum pumping operation on the transfer chamber where the target wafer is located, the vacuum degrees at multiple time points are compared with each first vacuum curve in the database to obtain a target first vacuum curve corresponding to the target wafer. Thereby, the type of outgassing amount corresponding to the target wafer can be determined, and the vacuum threshold value of the transfer chamber where the target wafer is located can be accurately obtained. Thus, the embodiment of this application accurately determines the vacuum threshold value of the transfer chamber where the target wafer is located based on the target first vacuum curve matching the target wafer. By avoiding the problem of a significant extension of the vacuum pumping time due to inaccurate setting of the vacuum threshold value, the measurement throughput of the transfer chamber can be improved.

[0019] Hereinafter, specific embodiments of the method, apparatus, device, medium, and product for determining a vacuum threshold value according to an embodiment of this application will be described. First, the method for determining a vacuum threshold value will be described below.

[0020] FIG. 1 is a schematic flowchart of the method for determining a vacuum threshold value. The method for determining a vacuum threshold value may be applied to the server side and may include the following S101 to S104.

[0021] In S101, after loading a target wafer into the transfer chamber of a charged particle beam imaging device, a vacuum pumping operation is performed on the transfer chamber.

[0022] In this embodiment, the evacuation operation refers to a process of removing air, non-condensable gases, moisture, etc. in the transfer chamber by using equipment such as a vacuum pump so as to achieve a relative vacuum state. It is used to adjust the degree of vacuum in the transfer chamber to achieve the wafer transfer condition for transmitting the target wafer in the transfer chamber to the main vacuum chamber.

[0023] In S102, the degree of vacuum at multiple time points in the process of performing the evacuation operation of the transfer chamber is obtained.

[0024] In this embodiment, during the process of performing the evacuation operation of the transfer chamber, the degree of vacuum in the transfer chamber changes in real time. That is, during the process of performing the evacuation operation, the degree of vacuum at each time point in the transfer chamber is not the same.

[0025] As an example, the server side installs a sensor capable of measuring and recording the degree of vacuum data in the transfer chamber in real time. After the target wafer enters the transfer chamber, the sensor is activated to start recording the degree of vacuum data at multiple time points in the transfer chamber (for example, every 1 second, every 5 seconds, or at a time interval set according to actual needs).

[0026] Here, the sensor may be a capacitive, piezoresistive or thermal conductivity vacuum gauge, and the degree of vacuum data includes a time stamp and the corresponding degree of vacuum value.

[0027] In S103, a target first degree-of-vacuum curve that matches the degree of vacuum at multiple time points is searched from each first degree-of-vacuum curve in the database. The database includes a plurality of first degree-of-vacuum curves and the corresponding degree-of-vacuum stability values. Each first degree-of-vacuum curve represents the change trend of the degree of vacuum after wafers with different outgassing amounts are carried into the transfer chamber.

[0028] In this embodiment, the database pre-stores multiple first vacuum degree curves, each first vacuum degree curve corresponding to a specific wafer outgassing amount and representing the trend of change in the vacuum degree of the transport chamber after loading the wafer for the corresponding outgassing amount.

[0029] For example, the server compares the recorded vacuum level data with the first vacuum level curve in the database to find the target first vacuum level curve that best matches the current vacuum level data.

[0030] Here, the matching process can be implemented using algorithms such as the least squares method, dynamic time-normalized (DTW), or machine learning models.

[0031] In S104, the vacuum stability value corresponding to the target first vacuum curve is determined as the target vacuum threshold for the transport chamber corresponding to the target wafer.

[0032] In this embodiment, the vacuum stability value is the vacuum level value corresponding to the point in the target first vacuum curve when the vacuum level shows a stabilizing trend.

[0033] For example, after the server finds the target first vacuum curve, it obtains a vacuum stability value from the target first vacuum curve and determines the vacuum stability value corresponding to that target first vacuum curve as the target vacuum threshold corresponding to the target wafer.

[0034] Subsequently, the server continues to monitor the vacuum level in the transport chamber. If the vacuum level is better than or equal to the target vacuum threshold, the transport mechanism is triggered to safely transfer the target wafer from the transport chamber to the main vacuum chamber for the next processing step.

[0035] Here, a higher vacuum level indicates a lower air pressure within the transport chamber. The transport mechanism may be a robotic arm, a transport belt, or other automated equipment, and the specific choice may depend on the layout of the production line and the size of the wafer. In the vacuum threshold determination method according to the embodiment of the present invention, a database is pre-set in which a corresponding first vacuum curve and a vacuum stability value corresponding to the first vacuum curve are stored after wafers with different outgassing amounts are loaded into the transport chamber. Then, the vacuum level at multiple points in time during the process of performing a vacuuming operation on the transport chamber where the target wafer is located is compared with each first vacuum curve in the database to obtain a target first vacuum curve corresponding to the target wafer. This makes it possible to determine the outgassing amount type corresponding to the target wafer and to accurately obtain the vacuum threshold of the transport chamber where the target wafer is located. In this way, the embodiment of the present invention accurately determines the vacuum threshold of the transport chamber where the target wafer is located by using a target first vacuum curve that matches the target wafer. This avoids the problem of a significant extension of the vacuuming time due to inaccurate setting of the vacuum threshold and improves the measurement throughput of the transport chamber.

[0036] As one possible embodiment, after S102, the vacuum threshold determination method further... The objective is to obtain the time duration of variation in the first vacuum curve from the start until the vacuum level reaches stability, This includes, when the difference between the fluctuating time length and the current actual vacuuming time length corresponding to performing the vacuuming operation of the transport chamber is greater than a preset interval time length, periodically acquiring the vacuum level of the transport chamber at multiple points in time within a preset period until a preset condition is met, thereby obtaining a target second vacuum level curve, The pre-set conditions are that the difference between the current actual vacuuming time of the transport chamber and the fluctuation time of the second vacuum level curve is less than or equal to a pre-set interval time, and the second vacuum level curve is a first vacuum level curve that matches the vacuum level at multiple points in time after the vacuum level has been periodically acquired in the database.

[0037] In S104, it may be specifically included in determining the vacuum level stability value corresponding to the target second vacuum level curve as the target vacuum level threshold of the transport chamber corresponding to the target wafer. In this embodiment, the fluctuation time length is the period from when the vacuum level fluctuates from the starting value until it reaches a stable state, that is, it refers to the predicted vacuuming time length corresponding to the vacuum level curve.

[0038] The current actual vacuuming time is used to represent the time elapsed from the start time when the transport chamber performs the vacuuming operation to the present time. For example, the current actual vacuuming time may be 5 seconds, 10 seconds, or 15 seconds. As an example, the server acquires the target first vacuum curve and then acquires the fluctuation time T1 corresponding to the target first vacuum curve based on the time corresponding to the first vacuum level in the target first vacuum curve and the time corresponding to the vacuum level that reaches the first stable state.

[0039] Next, the current actual vacuuming time T2 of the transport chamber is obtained, and ΔT is obtained by subtracting the current actual vacuuming time T2 from the fluctuating time T1. If ΔT is greater than a preset interval (e.g., 10 seconds), vacuum level data is periodically acquired at multiple points in time within a preset period (e.g., every 5 seconds) of the transport chamber.

[0040] Next, all acquired vacuum data is matched with each of the first vacuum curves pre-set in the database to find the first vacuum curve that matches the vacuum level at multiple points in time within the actual vacuuming time, and then the second vacuum curve is obtained.

[0041] If the difference between the current actual vacuuming time length (T2') of the transport chamber and the fluctuation time length (T1') of the second vacuum curve is less than or equal to a preset interval time length, the corresponding second vacuum curve is finally determined as the target second vacuum curve, and the stable vacuum value corresponding to the target second vacuum curve is determined as the target vacuum threshold corresponding to the target wafer. The above steps are repeated until this is done.

[0042] In this embodiment, the vacuum level of the transport chamber is periodically acquired at multiple points in time within a predetermined period, and then continuously matched to each first vacuum level curve in the database until the predicted vacuuming completion time is approached. By acquiring as many vacuum level data points as possible for the transport chamber, the accuracy of the matching is improved, and the vacuum level threshold of the transport chamber where the target wafer is located can be accurately determined.

[0043] As one possible embodiment, before periodically acquiring the vacuum level of the transport chamber at multiple points in time within a predetermined period, the vacuum level threshold determination method further... This may include determining a predetermined time period smaller than the difference between the fluctuating time period and the current actual vacuuming time period.

[0044] In this embodiment, assuming that the fluctuation time is 20 seconds and the current actual vacuuming time is 5 seconds, the difference between the fluctuation time and the current actual vacuuming time is 15 seconds. In other words, in this case, there are 15 seconds remaining until the predicted vacuuming is completed.

[0045] In this case, the pre-set period must be less than 15 seconds. If it exceeds 15 seconds, excessive vacuuming may occur, extending the vacuuming time and potentially reducing the measurement throughput of the transport chamber.

[0046] Furthermore, the pre-set period can be made as close as possible to the difference between the fluctuating time length and the current actual vacuuming time length. For example, assuming that the difference between the fluctuating time length and the current actual vacuuming time length is 15 seconds and the pre-set interval time length is 5 seconds, the vacuum threshold of the transport chamber where the target wafer is located is determined 5 seconds before the predicted end of vacuuming.

[0047] Therefore, the pre-set period can be directly set to 15-5=10 seconds. In this case, it is sufficient to obtain the vacuum level once periodically, i.e., perform a single matching verification with the first vacuum level curve in the database, thereby reducing the redundancy of calculations and lowering the consumption of computational resources.

[0048] This embodiment helps in performing periodic acquisition of vacuum levels based on a subsequent preset period by determining the length of a preset period based on the difference between the fluctuating time length and the current actual vacuuming time length. By acquiring as many vacuum levels as possible in the transport chamber, the accuracy of matching can be improved, and the vacuum level threshold of the transport chamber where the target wafer is located can be accurately determined.

[0049] As one possible embodiment, in S103, specifically, By fitting the vacuum levels at multiple points in time, a third vacuum curve of the transport chamber is obtained, This may include searching for a target first vacuum curve that matches a third vacuum curve from each first vacuum curve in the database.

[0050] In this embodiment, the third vacuum curve is a curve showing the trend of change in the vacuum level within the transport chamber of the target wafer, obtained by fitting it based on the vacuum levels at multiple points in time.

[0051] For example, during the process of vacuuming or maintaining a vacuum state in the transport chamber, the server uses a high-precision vacuum sensor to acquire vacuum data at multiple points in time in real time.

[0052] Next, the vacuum level data acquired at multiple points in time is input into a fitting algorithm, such as polynomial fitting, exponential fitting, or neural network fitting, to fit a third vacuum level curve. This third vacuum level curve can then accurately reflect the time-dependent changes in the vacuum level within the transport chamber where the target wafer is located.

[0053] Furthermore, a suitable matching algorithm is used to match the third vacuum level curve with each first vacuum level curve in the database. The matching algorithm can be used to compare curves based on characteristic parameters such as their shape, slope, maximum value, and minimum value.

[0054] Finally, based on the degree of matching (e.g., similarity, error, etc.), the first vacuum curve that best matches the third vacuum curve is selected as the target first vacuum curve.

[0055] In this embodiment, a third vacuum curve is obtained by fitting vacuum data at multiple points in time, and a target first vacuum curve that matches the third vacuum curve is searched from the database. This makes it possible to accurately determine the target vacuum threshold corresponding to the target wafer based on the target first vacuum curve in the database.

[0056] As one possible embodiment, after searching for a target first vacuum level curve that matches the vacuum level at multiple time points from each first vacuum level curve in the database, the vacuum level threshold determination method further... If a target first vacuum curve that matches the third vacuum curve does not exist in the database, process information will be output to indicate that process variation has occurred in the target wafer. The system may include updating a database in response to a user inputting a standard vacuum curve corresponding to a target wafer, and using the standard vacuum curve to represent the standard trend of vacuum changes after the target wafer has been loaded into the transport chamber.

[0057] In this embodiment, process information is output when matching fails and is used to inform the user that a process change has occurred in the target wafer. In other words, there is a difference between the process flow of the target wafer and the normal process flow corresponding to various wafers in the database.

[0058] Based on the process information provided, the user obtains the standard vacuum curve for the transport chamber where the target wafer is located, stores this standard vacuum curve in the database, and updates the database.

[0059] Exemplary, a standard vacuum curve can be obtained by transforming the standard pressure curve of the transport chamber in which the target wafer is located. The standard pressure curve is used to represent the standard changes in atmospheric pressure during the vacuuming process of the transport chamber in which the target wafer is located.

[0060] As shown in Figure 2, a schematic diagram of the standard pressure curve for the transport chamber in which the target wafer is located is provided. Here, the pressure in the transport chamber in which the target wafer is located decreases with increasing time and stabilizes until the end. Specifically, the standard pressure curve includes a total of four stages.

[0061] In the first stage (201), the gas within the chamber volume is primarily extracted using a pre-pump (generally a dry pump), also known as a rough pump. In actual machines, this stage is completed by the machine's high-speed dry pump, and after a short time, when the pressure reaches the molecular pump operating range, the second stage (202) begins. In this stage, the molecular pump begins to evacuate, primarily extracting gas adsorbed on the surface. As the pressure continuously decreases, the vacuum gradually improves, and as the gas adsorbed on the surface is gradually extracted, the third stage (203) begins, in which the diffusion of surface-released gas and internally dissolved gas is primarily extracted. Finally, the fourth stage (204) begins, and the pressure stabilizes.

[0062] As an example, the server first matches the collected third vacuum curves with each first vacuum curve in the database.

[0063] If a target first vacuum curve that matches the third vacuum curve does not exist in the database, process information is output indicating that a process variation has occurred in the target wafer. Here, the process information includes, but is not limited to, the wafer number, transport chamber number, and vacuum data.

[0064] The server then updates the database in response to the user's input of a standard vacuum curve corresponding to the target wafer, and stores the standard vacuum curve entered by the user in the database.

[0065] In this embodiment, if a target first vacuum curve that matches the third vacuum curve does not exist in the database, the database is immediately updated based on the standard vacuum curve corresponding to the target wafer entered by the user. In this way, it is possible to provide information in response to process variations and contribute to improving the reliability of subsequent database matching.

[0066] As one possible embodiment, prior to S104, the vacuum threshold determination method further... If a target first vacuum curve matching the third vacuum curve does not exist in the database, the rate of change of the first vacuum curve corresponding to the third vacuum curve and the rate of change of the second vacuum curve at the current vacuuming time corresponding to the vacuuming operation of the transport chamber for each first vacuum curve are obtained. The vacuum level comparison results are obtained by comparing the rate of change of the first vacuum level with each of the second vacuum level change rates, Based on the comparison results of the vacuum levels, the wafer transmission conditions corresponding to the target wafer are determined, The system may also include, when it is determined that the wafer transmission conditions have been met, transmitting the target wafer from the transport chamber to the main vacuum chamber.

[0067] In this embodiment, the first vacuum degree change rate is used to represent the change in vacuum degree in the third vacuum degree curve.

[0068] The second vacuum level change rate is used to represent the change in vacuum level at the current vacuuming time length corresponding to the third vacuum level curve in the first vacuum level curve.

[0069] The comparison results of the vacuum levels are used to show the relative magnitudes of the first vacuum level change rate and the second vacuum level change rate.

[0070] Wafer transmission conditions are used to describe the conditions that must be met when transmitting a target wafer from the transport chamber to the main vacuum chamber.

[0071] For example, if the server does not have a target first vacuum curve that matches the third vacuum curve in the database, it will acquire the rate of change of the first vacuum corresponding to the third vacuum curve in real time.

[0072] Next, based on the current vacuuming time corresponding to the third vacuum curve, the second vacuum level change rate for each first vacuum curve at the corresponding current vacuuming time is extracted from the database. Furthermore, the magnitude of the first vacuum level change rate for the third vacuum curve and the second vacuum level change rate for each first vacuum curve are compared to obtain a vacuum level comparison result.

[0073] Finally, based on the vacuum level comparison results, it is determined whether the target wafer meets the wafer transmission conditions according to the pre-set wafer transmission condition determination rules. If it is determined that the wafer transmission conditions are met, the wafer transmission device is started and the target wafer is transmitted from the transport chamber to the main vacuum chamber.

[0074] Selectively, the comparison results of vacuum levels may include two outcomes: one where the rate of change of the first vacuum level is greater than the rate of change of each second vacuum level, and another where the rate of change of the first vacuum level is smaller than the rate of change of each second vacuum level.

[0075] When the first vacuum degree change rate is greater than each of the second vacuum degree change rates, it can be determined that the vacuuming speed of the transport chamber where the target wafer is located is greater than the vacuuming speed of the transport chamber where each wafer is located in the database. The wafer transmission conditions can be set so that the time length of the target wafer in the transport chamber reaches the shortest transmission time among the transmission times corresponding to each first vacuum degree curve in the database.

[0076] When the first vacuum degree change rate is smaller than each of the second vacuum degree change rates, it can be determined that the vacuuming speed of the transport chamber where the target wafer is located is smaller than the vacuuming speed of the transport chamber where each wafer is located in the database. The wafer transmission conditions can be set so that the time length of the target wafer in the transport chamber reaches a preset multiple of the longest transmission time among the transmission times corresponding to each first vacuum degree curve in the database.

[0077] This embodiment provides a method for determining wafer transmission conditions by comparing the rate of change in vacuum when there is no target first vacuum curve in the database that matches the third vacuum curve. This ensures that each wafer is transmitted to the main vacuum chamber smoothly when the wafer satisfies the transmission conditions.

[0078] As one possible embodiment, when the comparison of vacuum levels shows that the rate of change of the first vacuum level is greater than the rate of change of each second vacuum level, the wafer transmission condition is that the time length of the target wafer in the transport chamber satisfies a preset minimum waiting time.

[0079] When the comparison of vacuum levels shows that the rate of change of the first vacuum level is smaller than the rate of change of each second vacuum level, the wafer transmission condition is that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber.

[0080] In this embodiment, the minimum waiting time is used to represent the shortest time that must be waited from the moment the wafer enters the transport chamber until it is transmitted to the main vacuum chamber.

[0081] For example, if the first vacuum degree change rate is greater than each of the second vacuum degree change rates, it can be determined that the vacuuming speed of the transport chamber where the target wafer is located is greater than the vacuuming speed of the transport chamber where each wafer in the database is located.

[0082] In other words, in this case, since it is possible to ensure that the vacuum level of the transport chamber where the target wafer is located satisfies the transmission requirement in a relatively short time, the wafer transmission conditions are set so that the time length of the target wafer in the transport chamber satisfies the preset minimum waiting time.

[0083] When the first vacuum degree change rate is smaller than each of the second vacuum degree change rates, it can be determined that the vacuuming speed of the transport chamber where the target wafer is located is smaller than the vacuuming speed of the transport chamber where each wafer in the database is located.

[0084] In other words, in this case, since it is possible to ensure that the vacuum level of the transport chamber where the target wafer is located satisfies the transmission requirement over a long period of time, the wafer transmission conditions are set so that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber.

[0085] In this embodiment, corresponding wafer transmission conditions are set based on the relative magnitudes of the first vacuum degree change rate and each second vacuum degree change rate. By transmitting the wafer to the main vacuum chamber when the wafer transmission conditions are met, it is possible to ensure that each wafer is smoothly transmitted to the main vacuum chamber.

[0086] One possible embodiment is that the wafer transmission condition is that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber.

[0087] After determining the wafer transmission conditions corresponding to the target wafer based on the vacuum level comparison results, the vacuum level threshold determination method further... To obtain the number of wafers in the transport chamber where the target wafer is located, When the number of wafers is single, control the system to connect the transport chamber and the main vacuum chamber, If there are multiple wafers, the system may also include controlling the moving assembly to remove wafers other than the target wafer from the transport chamber and to connect the transport chamber with the main vacuum chamber.

[0088] In this embodiment, the moving assembly is used to move a wafer. Exemplarily, the moving assembly may be a robotic arm.

[0089] The server first uses sensors to detect the number and position of wafers in the transport chamber, and then determines the position of the target wafer and the presence of other wafers within the transport chamber.

[0090] When the sensor detects that there is only one wafer in the transport chamber, that is, that the target wafer is the only wafer, it controls the system to turn on the isolation valve between the transport chamber and the main vacuum chamber, thereby connecting the transport chamber and the main vacuum chamber.

[0091] When the sensor detects that there are multiple wafers in the transport chamber, the moving assembly can first be controlled to remove any wafers other than the target wafer from the transport chamber and temporarily store them in another storage location or send them back to the wafer supply area. Next, the isolation valve between the transport chamber and the main vacuum chamber is controlled to turn on, connecting the transport chamber and the main vacuum chamber.

[0092] In this embodiment, by controlling the transport chamber and the main vacuum chamber to communicate with each other, the molecular pumps in the main vacuum chamber and the transport chamber can work together to perform the vacuuming operation. This prevents vacuum fluctuations in the main vacuum chamber and further shortens the vacuuming time of the transport chamber.

[0093] Based on the vacuum threshold determination method, the present application further provides specific embodiments of a vacuum threshold determination apparatus.

[0094] As shown in Figure 3, the vacuum threshold determination device 300 according to the embodiment of the present invention includes a transport chamber vacuum module 310, a vacuum acquisition module 320, a curve matching module 330, and a threshold determination module 340.

[0095] The transport chamber vacuum module 310 is used to perform a vacuum operation on the transport chamber after the target wafer has been loaded into the transport chamber of the charged particle beam imaging apparatus.

[0096] The vacuum level acquisition module 320 is used to acquire the vacuum level of the transport chamber at multiple points in time during the vacuuming operation.

[0097] The curve matching module 330 is used to search for a target first vacuum curve that matches the vacuum level at multiple points in time from each first vacuum curve in the database. The database contains multiple first vacuum curves and corresponding vacuum level stability values, and each first vacuum curve is used to represent the trend of change in vacuum level after wafers with different outgassing amounts are loaded into the transport chamber.

[0098] The threshold determination module 340 is used to determine the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold for the transport chamber corresponding to the target wafer.

[0099] As one possible embodiment, after searching for a target first vacuum level curve that matches the vacuum level at multiple time points from each first vacuum level curve in the database, the vacuum level threshold determination device 300 performs the following: A time length acquisition module used to obtain the fluctuation time length elapsed from the start until the vacuum level in the target first vacuum curve reaches stability, The system may further include a cyclic execution module used to obtain a target second vacuum curve by periodically acquiring the vacuum level of the transport chamber at multiple points in time within a predetermined period until a predetermined condition is met, when the difference between the fluctuating time length and the current actual vacuum time length corresponding to performing the vacuuming operation of the transport chamber is greater than a predetermined interval time length, The pre-set conditions are that the difference between the current actual vacuuming time length of the transport chamber and the fluctuation time length of the second vacuum level curve is less than or equal to a pre-set interval time length, and the second vacuum level curve is a first vacuum level curve that matches the vacuum level at multiple points in time after the vacuum level has been periodically acquired in the database.

[0100] Specifically, the threshold determination module 340 is used to determine the vacuum stability value corresponding to the target second vacuum curve as the target vacuum threshold for the transport chamber corresponding to the target wafer.

[0101] In one optional embodiment, before periodically acquiring the vacuum level of the transport chamber at multiple points in time within a predetermined period, the vacuum level threshold determination device 300 may further include a time length determination module used to determine a predetermined period length that is less than the difference between the fluctuating time length and the current actual vacuuming time length.

[0102] As one possible embodiment, the curve matching module 330 specifically A curve fitting unit used to obtain a third vacuum curve of a transport chamber by fitting the vacuum levels at multiple points in time, It includes a curve matching unit used to search for a target first vacuum curve that matches a third vacuum curve from each first vacuum curve in the database.

[0103] As one possible embodiment, after searching for a target first vacuum level curve that matches the vacuum level at multiple time points from each first vacuum level curve in the database, the vacuum level threshold determination device 300 further: The system may also include a process indication module used to output process indication information indicating that process variations have occurred in the target wafer when no target first vacuum curve matching the third vacuum curve exists in the database.

[0104] In response to a user inputting a standard vacuum curve corresponding to a target wafer, the database may be updated, and the standard vacuum curve may include a database update module that represents the standard trend of vacuum changes after the target wafer has been loaded into the transport chamber.

[0105] As one possible embodiment, before determining the vacuum level stability value corresponding to the target first vacuum curve as the target vacuum level threshold of the transport chamber corresponding to the target wafer, the vacuum level threshold determination device 300 further: A rate of change acquisition module is used to obtain the rate of change of the first vacuum corresponding to the third vacuum curve and the rate of change of the second vacuum at the current vacuuming time length corresponding to each first vacuum curve performing the vacuuming operation of the transport chamber, when no target first vacuum curve matching the third vacuum curve does not exist in the database. A rate of change comparison module used to obtain a comparison result of vacuum levels by comparing the rate of change of the first vacuum level with each of the second vacuum level change rates, A condition determination module used to determine wafer transmission conditions corresponding to a target wafer based on the vacuum level comparison results, The system may also include a wafer transmission module used to transmit a target wafer from a transport chamber to a main vacuum chamber when it is determined that the wafer transmission conditions are met.

[0106] One possible embodiment is that the wafer transmission condition is that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber.

[0107] After determining the wafer transmission conditions corresponding to the target wafer based on the vacuum level comparison results, the vacuum level threshold determination device 300 further: A data acquisition module used to obtain the quantity of wafers in the transport chamber where the target wafer is located, A transport chamber control module used to control the transport chamber and the main vacuum chamber to communicate when the number of wafers is single, Furthermore, if there are multiple wafers, the system may include a transport chamber control module used to control the moving assembly to remove wafers other than the target wafer from the transport chamber and to control the transport chamber to communicate with the main vacuum chamber.

[0108] Based on the vacuum threshold determination method, the present application further provides specific embodiments of a vacuum threshold determination device.

[0109] Figure 4 shows a schematic diagram of the hardware structure of a vacuum threshold determination device according to an embodiment of the present invention.

[0110] The vacuum threshold determination device may include a processor 401 and a memory 402 that stores computer program commands.

[0111] Specifically, the processor 401 described above may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0112] Memory 402 may include large-capacity memory for data or instructions. For example, memory 402 may include, but is not limited to, a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a Universal Serial Bus (USB) drive, or two or more combinations thereof. Where appropriate, memory 402 may include removable or non-removable (or fixed) media. Where appropriate, memory 402 can be located inside or outside the disaster recovery device of the integrated gateway. In certain embodiments, memory 402 is non-volatile solid memory.

[0113] The processor 401 realizes one of the vacuum threshold determination methods of the above embodiment by reading and executing computer program instructions stored in the memory 402.

[0114] In one example, the vacuum threshold determination device may further include a communication interface 403 and a bus 410. Here, as shown in Figure 4, the processor 401, memory 402, and communication interface 403 are connected via the bus 410 and complete mutual communication.

[0115] The communication interface 403 is primarily used to enable communication between each module, device, unit and / or equipment in the embodiments of the present application.

[0116] Bus 410 includes hardware, software, or both that interconnect components of a vacuum threshold determination device. For example, the bus may include, but is not limited to, an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industrial Standards Architecture (EISA) bus, a Front Side Bus (FSB), a Superconducting (HT) interconnect, an Industrial Standards Architecture (ISA) bus, an Infinite Bandwidth interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or two or more combinations thereof. Where appropriate, Bus 410 may include one or more buses. While the embodiments of this application describe and illustrate specific buses, any suitable bus or interconnect is considered hereby.

[0117] Furthermore, referring to the vacuum threshold determination method in the above embodiment, the embodiment of the present application can be realized by providing a computer storage medium. A computer program command is stored in the computer storage medium. When the computer program command is executed by a processor, one of the vacuum threshold determination methods of the above embodiment is realized.

[0118] Furthermore, referring to the vacuum threshold determination method in the above embodiment, the embodiment of the present application can be realized by providing a computer program product. When the instructions in the computer program product are executed by the processor of an electronic device, the electronic device is made to execute the vacuum threshold determination method according to any one of the embodiments of the present application described above.

[0119] Furthermore, this application is not limited to the specific configurations and processes described and illustrated above. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the process of the method of this application is not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications, and additions or change the order of the steps after understanding the spirit of this application.

[0120] The functional blocks shown in the above configuration block diagram may be implemented as hardware, software, firmware, or a combination thereof. When implemented as hardware, they may include, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, or functional cards. When implemented as software, the elements of this application are programs or code segments for performing the required tasks. The programs or code segments may be stored in a machine-readable medium or transmitted over a transmission medium or communication link by data signals contained in a carrier wave. "Machine-readable medium" may include any medium capable of storing or transmitting information. Examples of machine-readable mediums include electronic circuits, semiconductor memory devices, ROMs, flash memory, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, and radio frequency (RF) links. Code segments can be downloaded over computer networks such as the Internet or an intranet.

[0121] The exemplary embodiments referred to herein describe several methods or systems based on a series of steps or apparatus. However, the present invention is not limited to the order of the steps described above; that is, the steps may be performed in the order described in the embodiments or in a different order, or some steps may be performed simultaneously.

[0122] The embodiments of this disclosure have been described above with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowcharts and / or block diagrams, and each combination of blocks in the flowcharts and / or block diagrams, are implemented by computer program directives. These computer program directives are provided to a processor of a general-purpose computer, a dedicated computer, or other programmable data processing device and used to generate a machine, and these directives, executed by the processor of the computer or other programmable data processing device, enable the implementation of the functions / operations specified in one or more blocks of the flowcharts and / or block diagrams. Such a processor may be, but is not limited to, a general-purpose processor, a dedicated processor, a special application processor, or a field-programmable logic circuit. Also, as can be understood, each block in the block diagrams and / or flowcharts, and each combination of blocks in the block diagrams and / or flowcharts, may be implemented by dedicated hardware that performs the specified function or operation, or by a combination of dedicated hardware and computer directives.

[0123] The above description is merely a specific embodiment of the present application, and for the convenience and brevity of description, it will be obvious to those skilled in the art that the specific operating processes of the systems, modules, and units described above refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here. To make it clear, the scope of protection of this application is not limited thereto, and all kinds of equivalent modifications or substitutions that are readily conceivable to those skilled in the art within the technical scope disclosed herein are included in the scope of protection of this application.

Claims

1. After loading the target wafer into the transport chamber of the charged particle beam imaging apparatus, a vacuum operation is performed on the transport chamber. To obtain the degree of vacuum in the transport chamber at multiple points in time during the process of performing the vacuuming operation, A target first vacuum level curve matching the vacuum level at the multiple time points is searched from each first vacuum level curve in the database, the database includes multiple first vacuum level curves and corresponding vacuum level stability values, and each first vacuum level curve is used to represent the trend of change in vacuum level after wafers with different outgassing amounts are loaded into the transport chamber, This includes determining the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer, A method for determining a vacuum threshold characterized by the following features.

2. After searching for a target first vacuum level curve that matches the vacuum level at the multiple time points from each first vacuum level curve in the database, the vacuum level threshold determination method further: To obtain the time length of variation from the start until the vacuum level in the aforementioned target first vacuum level curve reaches stability, The procedure includes, if the difference between the aforementioned fluctuating time length and the current actual vacuuming time length corresponding to performing the vacuuming operation of the transport chamber is greater than a predetermined interval time length, periodically acquiring the vacuum level of the transport chamber at multiple points in time within a predetermined period until a predetermined condition is met, thereby obtaining a target second vacuum level curve, The aforementioned pre-set conditions are that the difference between the current actual vacuuming time length of the transport chamber and the fluctuation time length of the second vacuum level curve is less than or equal to the pre-set interval time length, and that the second vacuum level curve is a first vacuum level curve that matches the vacuum level at the multiple time points after the vacuum level has been periodically acquired in the database. Determining the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer is: This includes determining the vacuum stability value corresponding to the target second vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer. The vacuum threshold determination method according to feature 1.

3. Before periodically acquiring the vacuum level of the transport chamber at multiple points in time within a predetermined period, the vacuum level threshold determination method further: This includes determining the length of a preset period that is smaller than the difference between the aforementioned fluctuating time length and the current actual vacuuming time length, The vacuum threshold determination method according to feature 2.

4. Searching for a target first vacuum level curve that matches the vacuum level at the multiple time points from each first vacuum level curve in the database is: The vacuum levels at the aforementioned multiple time points are fitted to obtain a third vacuum curve for the transport chamber, This includes searching for a target first vacuum curve that matches the third vacuum curve from each first vacuum curve in the database, A method for determining a vacuum threshold according to any one of claims 1 to 3.

5. After searching for a target first vacuum level curve that matches the vacuum level at the multiple time points from each first vacuum level curve in the database, the vacuum level threshold determination method further: If no target first vacuum curve matching the third vacuum curve exists in the database, process information is output to indicate that a process variation has occurred in the target wafer. The system includes updating the database in response to a user inputting a standard vacuum curve corresponding to the target wafer, and using the standard vacuum curve to represent the standard trend of vacuum changes after the target wafer has been loaded into the transport chamber. The vacuum threshold determination method according to feature 4.

6. Before determining the vacuum stability value corresponding to the target first vacuum curve as the target vacuum threshold of the transport chamber corresponding to the target wafer, the vacuum threshold determination method further includes: If no target first vacuum curve matching the third vacuum curve exists in the database, the first vacuum rate change corresponding to the third vacuum curve and the second vacuum rate change at the current vacuum time length corresponding to each of the first vacuum curves performing the vacuuming operation of the transport chamber are obtained. The vacuum degree comparison result is obtained by comparing the first vacuum degree change rate with each of the second vacuum degree change rates, Based on the vacuum level comparison results, the wafer transmission conditions corresponding to the target wafer are determined. The process includes, when it is determined that the wafer transmission conditions are met, transmitting the target wafer from the transport chamber to the main vacuum chamber. The vacuum threshold determination method according to feature 4.

7. When the vacuum level comparison result indicates that the first vacuum level change rate is greater than each of the second vacuum level change rates, the wafer transmission condition is such that the time length of the target wafer in the transport chamber satisfies a preset minimum waiting time. When the vacuum level comparison result indicates that the first vacuum level change rate is smaller than each of the second vacuum level change rates, the wafer transmission condition is that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber. The method for determining the vacuum threshold according to feature 6.

8. The wafer transmission condition is that the vacuum level of the transport chamber where the target wafer is located is equal to the vacuum level of the main vacuum chamber. After determining the wafer transmission conditions corresponding to the target wafer based on the vacuum level comparison results, the vacuum level threshold determination method further: To obtain the quantity of wafers in the transport chamber where the target wafer is located, When the number of wafers is single, control the transport chamber and the main vacuum chamber to communicate with each other. If there are multiple wafers, the moving assembly is controlled to remove wafers other than the target wafer from the transport chamber and to connect the transport chamber and the main vacuum chamber. The vacuum threshold determination method according to feature 7.

9. Processor and Includes memory in which computer program instructions are stored, When the processor executes the computer program command, it implements the vacuum threshold determination method according to any one of claims 1 to 8. An electronic device characterized by the following features.

10. A computer-readable storage medium, The aforementioned computer-readable storage medium stores computer program instructions. When the computer program command is executed by the processor, the vacuum threshold determination method according to any one of claims 1 to 8 is realized. A computer-readable storage medium characterized by the following features.

11. A computer program product, When a command in the aforementioned computer program product is executed by the processor of an electronic device, the electronic device is made to execute the vacuum threshold determination method described in any one of claims 1 to 8. A computer program product characterized by the following features.

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