Precise automated control of sheet extraction process

Abstract

A sample preparation method for electron microscopy imaging comprises the following steps: providing a substrate in an electron microscope system comprising a probe for manipulating a free sample of the substrate; applying a current flow between a stage of the system and the probe; detecting a first current flow change associated with the probe contacting the sample; upon detecting the first current flow change, extracting a sample from the substrate using a probe; detecting a second current flow change associated with extracting the sample from the substrate; and confirming that the sample has been extracted from the substrate based at least in part on the second current flow change.

Description

Background Technology

[0001] In both manual and automated transmission electron microscopy (TEM) section preparation, the extraction step is crucial for process success. In manual operation, the user controls a nanomanipulator to maneuver around the section, including adjusting the contrast as the nanomanipulator contacts the section. However, inexperienced operators may fail to properly assess the situation, especially when preparing novel sample types. In automated processes, there is no feedback loop to confirm correct section preparation (e.g., no feedback loop to confirm the section has been correctly attached to the nanomanipulator). Failures occurring during the attachment of the section to the nanomanipulator tip are often only detected in subsequent steps, such as during the welding process. Invention Summary

[0002] According to one embodiment, a sample preparation method for electron microscopy imaging includes: providing a substrate in an electron microscopy system, the system including a probe for manipulating the substrate to free a sample; applying a current flow between the system stage and the probe; detecting a first current flow change related to the probe contacting the sample; after detecting the first current flow change, extracting the sample from the substrate using the probe; detecting a second current flow change related to the extraction of the sample from the substrate; and confirming, at least in part, that the sample has been extracted from the substrate based on the second current flow change.

[0003] The method may include various optional implementations. The method may further include: after confirming that the sample has been extracted from the substrate, mounting the sample onto a sample carrier of the system using a probe; detecting a third current flow change; and confirming that the sample has been mounted based at least in part on the third current flow change. The method may further include: after confirming that the sample has been mounted, separating the probe from the sample; detecting a fourth current flow change; and confirming that the sample has been separated from the probe based at least in part on the fourth current flow change. The applied current flow may be between a reference level and 1 mA. The first current flow change may be the difference between the applied current flow's current level changing from the reference level to the applied current flow's current level. The second current flow change may be the difference between the applied current flow's current level changing from the applied current flow's current level to the reference level. The method may further include recording conditions associated with the first and second current flow changes. The conditions may include one or more of pattern depth and pattern time.

[0004] According to another embodiment, a sample preparation system for electron microscopy imaging includes: an ion beam column, an electron beam column, a stage for supporting a substrate, a probe, a current source configured to provide current between the probe and the stage, and a controller for controlling system operation. The controller includes a memory storing computer instructions for: detecting current flow between the probe and the stage based on contact between the probe and the substrate sample; separating the sample from the substrate using an ion beam if current flow is detected; detecting changes in current flow related to sample extraction from the substrate; and confirming, at least in part, that the sample has been extracted from the substrate based on these changes in current flow.

[0005] The system may include various optional implementations. The applied current flow level may be between a reference level and 1mA. The current flow variation may be the difference between the applied current flow level changing from the reference level to the applied current flow level. The instructions may also include recording conditions associated with this current flow variation. The conditions may include one or more of pattern depth and pattern time.

[0006] According to another embodiment, a non-transitory computer-readable medium stores instructions executable by one or more processors of an electron microscope system for causing the one or more processors to perform operations including: controlling current flow between a system stage and a system probe; detecting a first current flow change in response to contact between a sample and the probe; using the probe to control the extraction of a sample from a substrate upon detection of the first current flow change; detecting a second current flow change associated with the extraction of the sample from the substrate; and confirming, at least in part, that the sample has been extracted from the substrate based on the second current flow change.

[0007] The non-transitory computer-readable medium may include various alternative implementations. The instructions may include: controlling a probe to mount the sample onto a system surface, upon confirmation that the sample has been extracted from the substrate; detecting a third current flow change; and confirming sample mounting based at least in part on the third current flow change. The applied current flow may be between a reference level and 1 mA. The first current flow change may be the difference between the applied current flow's current level and the reference level. The second current flow change may be the difference between the applied current flow's current level and the reference level. The instructions may also include recording processing conditions associated with the first and second current flow changes. The conditions may include one or more of pattern depth and patterning time. Attached Figure Description

[0008] The foregoing aspects of this disclosure and its many accompanying advantages will become more readily understood and thus more deeply appreciated when taken in conjunction with the accompanying drawings and the following detailed description.

[0009] Figure 1 This is a schematic diagram of an example dual-beam system used for sample preparation according to various embodiments of the present disclosure.

[0010] Figure 2 This is a block diagram of an example computer system that can be used in conjunction with systems and methods according to various embodiments of this disclosure.

[0011] Figure 3A This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0012] Figure 3B This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0013] Figure 3C This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0014] Figure 4A This is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0015] Figure 4B This is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0016] Figure 4C This is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0017] Figure 5A This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0018] Figure 5B This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0019] Figure 5C This is a schematic diagram illustrating the extraction of thin slices from a whole sample according to various embodiments of the present disclosure.

[0020] Figure 6A This is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0021] Figure 6BThis is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0022] Figure 6C This is a schematic diagram illustrating the transfer of a sheet onto a sheet carrier (e.g., a transmission electron microscope (TEM) grid) according to various embodiments of the present disclosure.

[0023] Figure 7 This is a flowchart of a method for precisely controlling the extraction and transfer of thin slices according to various embodiments of the present disclosure.

[0024] Figure 8 This is a flowchart of a computer-implemented method for precisely controlling the extraction and transfer of thin slices according to various embodiments of the present disclosure. Detailed Explanation

[0025] Although exemplary embodiments have been illustrated and described, those skilled in the art will understand that various modifications may be made thereto without departing from the spirit and scope of this disclosure.

[0026] Charged particle microscopy is applied across multiple industries, including the semiconductor industry, to analyze micrometer- and nanometer-scale structures. For example, semiconductor devices can include nanoscale transistors densely packed within a silicon wafer. Images obtained using charged particle microscopy can be used to improve process control, evaluate the quality of manufactured devices, and increase yield. Taking semiconductor devices as an example, objects such as field-effect transistors (FETs) can be formed in large silicon wafers, adjacent to multiple structures including other FETs, vias, diode junctions, etc. Due to the extremely small size and dense packing of these components, careful sample preparation can improve the imaging quality of these devices.

[0027] Imaging samples using charged particle microscopy can include using transmission electron microscopy (TEM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), or related techniques. To image samples using these techniques, a wafer needs to be prepared and extracted from a large substrate (e.g., a silicon wafer). The wafer may contain structures that constitute a device (e.g., a FET). The preparation and extraction of the wafer can be accomplished using a dual-beam charged particle microscopy system, which typically includes a focused ion beam (FIB) and a SEM. Although much of this invention has been discussed in relation to dual-beam systems, those skilled in the art will recognize that any of the embodiments described herein can be applied to FIB systems, FIB-SEM systems, FIB-laser systems, FIB-SEM-laser systems, etc. During wafer formation, FIB is used to remove material from the substrate, leaving the wafer as part of the remaining material, while SEM is used for imaging to guide the FIB process. This process has become a standard method in many industries, not just the semiconductor industry, and can be used to image and analyze almost any type of micron- or nanometer-scale structure embedded in a surrounding substrate.

[0028] TEM sheet preparation can be accomplished through manual or automated processes. In manual operation, the user manually controls nanomanipulators around the sheet. However, inexperienced operators may fail to properly assess the situation, leading to errors that cause extraction or transfer failures. Automated processes lack feedback loops, and faults that occur during extraction are not detected until after the sheet has been removed. Earlier fault detection allows operators to efficiently fine-tune process parameters. Various embodiments of this disclosure can improve the robustness of the extraction step to 95%. In comparison, the success rate for inexperienced operators is only about 86%. In other words, embodiments of this disclosure can improve the success rate of TEM sheet preparation by 10%. Various embodiments of this disclosure enable more precise control in the extraction and mesh welding steps of the TEM sheet preparation process, whether manual or automated.

[0029] Several steps are required between attaching and welding the sheet blocks to the sheet support (e.g., a TEM grid). Each step takes an average of about 2 minutes. Since throughput is just as important as robustness, earlier detection of problems will save time and cost in TEM sheet preparation. Furthermore, any failure between the attachment and welding operations will trigger a cleaning process for the nanomanipulator needle to remove sheet blocks or residue. The nanomanipulator needle must be cleaned to prepare for the next sheet extraction. Needle cleaning can take tens of minutes or require replacing the entire needle, depending on the tip length and thickness. Reducing the need for needle cleaning will further reduce needle consumption and shorten needle replacement intervals.

[0030] Embodiments of this disclosure provide contact detection between the nanomanipulator needle and the sheet, which can provide important information about the progress of the extraction process, including whether a successful connection has been established between the needle and the sheet block, the status of subsequent cutting steps, and whether the sheet block has been successfully welded to the sheet carrier. This feedback mechanism provides both manual operators and automated applications with the opportunity to correct operations and successfully complete the extraction process.

[0031] Figure 1 A schematic diagram of an example dual-beam system 100 according to certain embodiments is shown. Although examples of applicable hardware are given below, this disclosure is not limited to implementation in any particular type of hardware. The various embodiments described herein can be implemented by one or more algorithms executed by a computing system connected to system 100.

[0032] The dual-beam system 100 is equipped with an SEM 141 and a power supply and controller 145. An electron beam 143 is emitted from the cathode 152 by applying a voltage between the cathode 152 and the anode 154. The electron beam 143 is focused into a small spot by a condenser lens 156 and an objective lens 158. Two-dimensional scanning is achieved by a deflector 160. The operation of the condenser lens 156, objective lens 158, and deflector 160 is controlled by the power supply and controller 145.

[0033] The electron beam 143 can be focused onto a substrate 122 located on a stage 125 within the lower chamber 126. The substrate 122 can be located on the surface of the stage 125 or on a sheet carrier 124 extending from the surface of the stage 125.

[0034] When electrons in the electron beam strike the substrate 122, secondary electrons are emitted. These secondary electrons can be detected by the secondary electron detector 140. In some embodiments, a STEM detector 162 located below the sheet carrier 124 and the stage 125 can collect electrons passing through the sample mounted on the TEM sample holder.

[0035] System 100 also includes a FIB system 111, which includes a vacuum chamber housing an ion column 112. The ion column 112 includes an ion source 114 and a focusing column 116, which includes a extraction electrode and an electrostatic optical system. The axis of the focusing column 116 can be tilted relative to the axis of the electron column 141, for example, at 52 degrees. The ion column 112 includes an ion source 114, an extraction electrode 115, a focusing element 117, and a deflection element 120. These components work together to form a focused ion beam 118. The focused ion beam 118 originates from the ion source 114, passes sequentially through the focusing column 116, and is emitted toward a substrate 122 via an electrostatic deflection device (illustrated as 120). The substrate 122 may be a semiconductor wafer located on a movable stage 125 within a lower chamber 126. In some embodiments, the sample may be located on a sheet carrier 124, which may be a sheet block extracted from the substrate 122. The sheet block can then be further processed by FIB to form a final sheet of the desired thickness, using methods described in this disclosure.

[0036] The stage 125 is movable in the horizontal plane (X and Y axes) and the vertical direction (Z axis). The stage 125 is also capable of tilting and rotating about the Z axis. In some embodiments, a separate TEM sample stage may be used. This TEM sample stage is also movable in the X, Y, and Z axis directions and is tiltable and rotatable. In some embodiments, the tilting of the stage 125 / sheet carrier 124 may be in or out of the incident plane of the ion beam 118, while rotation is performed about the axis of the ion beam 118. This relationship is maintained consistently when discussing sample rotation and tilting in the context of illustrating the disclosed technology herein. Of course, the opposite definition may also be used, but it remains within the scope of this disclosure.

[0037] Door 161 can be opened to place substrate 122 on stage 125. Depending on the tilt angle of stage 125 / sheet carrier 124, the Z-axis direction will be aligned with the optical axis direction of the associated column. For example, during the data acquisition phase of this disclosure, the Z-axis direction can be parallel to the FIB optical axis (i.e., the direction shown by ion beam 118). In this coordinate system, the X and Y axes are determined with reference to the Z-axis. For example, the X-axis could be... Figure 1 The direction of entry and exit within the plane, while the Y-axis is in... Figure 1 Within the plane, the three axes remain perpendicular to each other.

[0038] An ion pump 168 is used to evacuate the neck region. Chamber 126 is evacuated by a turbomolecular pump and mechanical pump system 130 controlled by a vacuum controller 132. This vacuum system can provide approximately 1 × 10⁻⁶ ppm within chamber 126. -7 Torr up to 5×10 -4Torr's vacuum. If etching assist gas, etching suppressor gas, or deposition precursor gas is used, the chamber background pressure may increase, typically reaching approximately 1 × 10⁻⁶. -5 Torr.

[0039] A high-voltage power supply provides an appropriate accelerating voltage to the electrodes in the focusing column 116 to excite and focus the ion beam 118. When the ion beam strikes the substrate 122, it sputters material, physically removing it from the sample. Alternatively, the ion beam 118 can also decompose precursor gases to deposit material.

[0040] A high-voltage power supply 134 is connected to the ion source 114 and the corresponding electrodes in the focusing column 116 to form an ion beam 118 of approximately 1 keV to 60 keV and direct it toward the sample. A deflection controller and amplifier 136 operate according to a predetermined pattern provided by a pattern generator 138 and is connected to a deflection element 120, thereby allowing manual or automatic control of the ion beam 118 to trace a corresponding pattern on the upper surface of the substrate 122. As is well known in the art, in some systems, a deflection plate is placed before the final lens. When a blanking controller (not shown) applies a blanking voltage to the blanking electrode, the beam blanking electrode (not shown) within the ion beam focusing column 116 causes the ion beam 118 to strike the blanking aperture (not shown) instead of the substrate 122.

[0041] Ion source 114 typically provides an ion beam based on its type. In some embodiments, ion source 114 is a liquid metal ion source, for example, providing a gallium ion beam. In other embodiments, ion source 114 may be a plasma-type ion source capable of delivering a variety of different ion species, such as oxygen, xenon, and nitrogen. Ion source 114 is typically capable of focusing a beam to a sub-1 / 10 micrometer width at substrate 122 or sheet carrier 124 for modifying substrate 122 by ion milling, ion-induced etching, material deposition, or for imaging substrate 122.

[0042] A charged particle detector 140, such as an Everhart-Thornley detector or a multichannel board, for detecting secondary ion or electron emissions, is connected to video circuitry 142, which supplies drive signals to video monitor 144 and receives deflection signals from system controller 119. The position of the charged particle detector 140 within the lower chamber 126 may vary in different embodiments. For example, the charged particle detector 140 may be coaxial with the ion beam and have an aperture allowing the ion beam to pass through. In other embodiments, secondary particles may be collected by a final lens and then deflected off-axis for collection.

[0043] Micromanipulator 147 can precisely move an object within a vacuum chamber. Micromanipulator 147 may include a precision electric motor 148 located outside the vacuum chamber to provide control of a component 149 located within the vacuum chamber in the X, Y, Z, and θ directions. Micromanipulator 147 may be equipped with different end effectors for manipulating small objects. In the embodiments described herein, the end effector is a fine probe 150.

[0044] The gas delivery system 146 extends into the lower chamber 126 to introduce and direct gaseous vapor toward the substrate 122. For example, iodine may be delivered to enhance etching, or a metal-organic compound may be delivered to deposit metal.

[0045] System controller 119 controls the operation of the various components of the dual-beam system. Through system controller 119, a user can input commands via a conventional user interface (not shown) to scan the ion beam 118 or electron beam 143 in a desired manner. Alternatively, system controller 119 can also control the dual-beam system according to program instructions stored in memory 121. In some embodiments, the dual-beam system integrates image recognition software that can automatically identify target areas, and then the system can extract samples manually or automatically according to the methods of this disclosure. For example, the system can automatically locate similar features on a semiconductor wafer comprising multiple devices and sample these features on different (or identical) devices.

[0046] When operating according to the techniques described herein, system 100 images the working surface (e.g., a cut surface) of sample 123, which is a sheet previously removed from a substrate. In this example, the sheet, approximately 1 micrometer thick, may be attached to sheet carrier 124. The working surface, as referred to herein, is the side surface of the sheet that needs to be thinned to the final sheet thickness. Sample 123 may include structures that need to be aligned / oriented with ion beam 118 in rotation and / or tilt so that structures requiring subsequent imaging are not removed during the final sheet formation process. Images of the newly exposed surface may be acquired via electron column 141 or FIB 111.

[0047] Each material layer of sample 123 can be removed from the working surface. The layer removal process can be performed using FIB milling or ion-induced etching with a gas precursor. In some embodiments, material layers can be removed in smaller "slices," for example, sequentially removing slices approximately 1 to 5 nanometers thick. After each slice is removed, the newly exposed surface is imaged. The image acquisition and slice removal process can be repeated 25, 50, 75, or 100 times, or any other number of times as described herein. The working surface of the slice may reveal structures required for imaging and / or analysis, such as including… FET device circuitry.

[0048] Removing a material layer from sample 123 can be achieved by guiding FIB 111 in a pattern to a portion of sample 123. For example, an ion beam can perform a raster scan on a region of the surface of sample 123 to remove the desired material layer. Embodiments of this disclosure provide methods and systems for ion beam deflection and for removing a desired material layer from sample 123 using a deflected ion beam.

[0049] Figure 2 A block diagram of an example computer system that can be used in conjunction with systems and methods according to embodiments of this disclosure is shown. Any computer system mentioned herein may employ any suitable number of subsystems. Examples of such subsystems are shown in... Figure 2 The computer system 200 shown is included. In some embodiments, the computer system includes a single computer device, with subsystems being components of the computer device. In other embodiments, the computer system may include multiple computer devices, each of which is a subsystem and has internal components. The computer system may include desktop computers, laptops, tablets, mobile phones, and other mobile devices.

[0050] Figure 2 The subsystems shown are interconnected via system bus 227. Other subsystems, such as printer 224, keyboard 228, storage device 229, monitor 226 (e.g., display screen, such as LED), which is connected to display adapter 282, are also shown. Peripheral devices and input / output (I / O) devices are connected to the computer system via I / O controller 221 and can be connected to the computer system in various ways known in the art, such as I / O ports 225 (e.g., USB, etc.). For example, I / O port 225 or external interface 281 (such as Ethernet, Wi-Fi, etc.) can be used to connect computer system 200 to a wide area network (such as the Internet), a mouse input device, or a scanner. Through the interconnection of system bus 227, the central processing unit 223 can communicate with various subsystems and control the execution of multiple instructions from system memory 222 or storage device 229 (such as a hard disk or optical disk), as well as the exchange of information between subsystems. System memory 222 and / or storage device 229 may be computer-readable media. Another subsystem is a data collection device 285, such as a camera, microphone, accelerometer, etc. Any data described herein may be output from one component to another and may be output to a user.

[0051] A computer system may include multiple identical components or subsystems, interconnected for example via an external interface 281, an internal interface, or a connectable / removable storage device. In some embodiments, the computer system, subsystem, or device may communicate over a network. In this case, one computer may be considered a client and another a server, both belonging to the same computer system. The client and server may each contain multiple systems, subsystems, or components.

[0052] Figures 3A-3C The process of extracting slices from a whole sample is shown. Figures 3A-3C A TEM sheet preparation system 300 including a probe 302 is shown. The term "probe" is used interchangeably herein with nanomanipulators, needles, etc. In at least some embodiments, the probe 302 may be an EasyLift nanomanipulator from Thermo Fisher Scientific. The system 300 may also include a monolithic sample 304 from which a sheet 306 is extracted. The sheet 306 can be processed from the monolithic sample 304 using milling techniques known in the art. Therefore, the probe 302 can be attached to the sheet 306 to sever any remaining connection between the sheet 306 and the monolithic sample 304, as understood by those skilled in the art. Figure 3B This shows the contact between probe 302 and sheet 306. Figure 3C The diagram illustrates how probe 302 separates or releases sheet 306 from the bulk sample 304 for transfer to another surface for further processing and / or imaging. Potential failures during extraction include unsuccessful bonding of sheet 306 to probe 302, and / or failure of sheet 306 to adequately sever its connection to the bulk sample 304.

[0053] like Figures 3A-3C The thin-slice extraction shown can be performed manually or through an automated system. Both methods carry the risk of extraction failure. Manual extraction is riskier for inexperienced operators who are unfamiliar with the parameters required for successful extraction, potentially leading to the loss of unique samples. The criteria for evaluating nanomanipulator placement are subjective and require refinement through extensive operational experience. The success of manual extraction depends entirely on the operator's experience. For automated systems, the extraction process typically relies entirely on image processing. Furthermore, there is a risk of unnecessary sample loss when the image processing system produces false negatives. Any errors can lead to a time-consuming needle cleaning process.

[0054] Figures 4A-4C The process of transferring a thin sheet to a thin sheet carrier is shown. Figures 4A-4C A TEM sheet preparation system 300 according to any embodiment of the present disclosure is shown, including a probe 302 and a sheet 306. Figure 4AThe image shows a probe 302 with a sheet 306 attached approaching a sheet carrier 402. The sheet 306 can be attached to or attached to a sample holder, stage, or other arbitrary surface for imaging or further processing. Figure 4B The sheet 306 is shown to be welded or otherwise attached to the sheet carrier 402. Figure 4C The separation between probe 302 and sheet 306 is shown after the transfer is complete. During the transfer process, there is a risk that the sheet 306 may not be successfully welded to the sheet carrier 402, and / or that the sheet 306 may not be adequately severed from the probe 302.

[0055] Various embodiments of this disclosure utilize electric current to detect contact between the probe and the sample, and between the sample and the sample carrier. Contact detection and confirmation between the probe and the sample (or sheet carrier) provide reliable information that can be processed by a manual operator or utilized by an automated system, thereby improving the performance of both methods.

[0056] Figures 5A-5C The process of extracting slices from a whole sample is shown. Figures 5A-5C A TEM section preparation system 500 is shown, including a probe 302 as illustrated in the other figures above. The system 500 may also include a monolithic sample 304 from which a section 306 can be extracted. For example, the section 306 may be a unique sample milled from the monolithic sample 304, which will be removed for further evaluation and processing. Figure 5A The system 500 also includes a current source 502 for detecting contact between the probe 302 and the sheet 306 according to embodiments of the present disclosure. The current source 502 may be connected between different embodiments of the system 500 to form a current loop. In some embodiments, the current source 502 may be located between the sheet 306 and the probe 302. In other embodiments, the current source 502 may be located between the sample-supporting stage, a monolithic stage, a composite stage (not shown), etc., and the probe 302.

[0057] In at least some embodiments, the current source 502 includes a maximum current level that can be applied to the system 500. By monitoring the current flow of the current source 502, embodiments of the present disclosure can effectively detect contact between the sheet 306 and the probe 302, and between the sheet 306 and the sample carrier, the latter of which will be described in detail below. Current readings can be output and provided as input to other components of the system, such as the operating system, to guide subsequent operation of the system. According to some embodiments, the system 500 may also include an ammeter 504 or a similar device (such as a multimeter, dedicated circuitry, picoammeter, current probe, clamp meter, etc.) for measuring changes in current flow as described in embodiments of the present disclosure. In at least some embodiments, dedicated circuitry may be implemented to measure current values. In exemplary embodiments, existing systems may include components for measuring current, which may be modified to further monitor changes in current flow as described in embodiments of the present disclosure.

[0058] like Figure 5A As shown, probe 302 is not in contact with sheet 306, and sheet 306 is interconnected with the overall sample 304. Therefore, the current loop is not closed, and there is no current flow between probe 302 and sheet 306. A current flow can be applied between the stage of system 500 and probe 302 and sheet 306. This current flow can be a reference current flow with a reference current level greater than or equal to 1 pA. In other words, when there is no electrical contact between probe 302 and sheet 306, the current flow is at the noise level of the measuring device (e.g., approximately 1 pA).

[0059] Figure 5B This illustration shows the contact between probe 302 and sheet 306 when sheet 306 is connected to the monolithic sample 304. The contact of probe 302 with sheet 306 causes a first change in current flow, which can be detected by ammeter 504 or a similar device. This change in current flow indicates that the connection between sheet 306 and probe 302 is sufficiently strong. For example, if the current value reaches or exceeds a preset value, the connection between sheet 306 and probe 302 is considered sufficiently strong, allowing sheet 306 to be removed from the monolithic sample 304 without accidental breakage or similar incidents. After detecting the first change in current flow, probe 302 can be used to extract sheet 306 from the monolithic sample 304, such as... Figure 5C As shown.

[0060] According to some embodiments, during the extraction of sheet 306 from whole sample 304 (e.g.) Figure 5CAs shown, a second current flow change can be detected. This second current flow change indicates that the sheet 306 has been successfully separated from the bulk sample 304. For example, complete separation of the sheet 306 from the bulk sample 304 would interrupt the current loop and cause the current flow and current value detected by the system to be interrupted. The extraction of the sheet 306 from the bulk sample 304 can be confirmed at least in part based on the second current flow change. Therefore, embodiments of this disclosure can detect the electrical contact between the probe 302 and the sheet 306 at each step of the sheet block extraction. The detected current flow change can provide clear quantitative and qualitative information for users of automated processes and manually controlled nanomanipulators to determine the integrity of contact and extraction.

[0061] Figures 6A-6C The process of transferring a thin sheet to a thin sheet carrier is shown. Figures 6A-6C A TEM thin-film preparation system 500 is shown, including a probe 302 and a thin film 306 as described in the foregoing figures. System 500 also includes a current source 502 and may include an ammeter 504 or other current measuring devices known in the art (such as a multimeter, dedicated circuit, picoammeter, current probe, clamp meter, etc.). After confirming that the thin film 306 has been extracted from the monolithic sample 304 (e.g., ...), the thin film 306 is prepared. Figure 5C In the case shown, probe 302 can be used to mount sheet 306 onto a surface of system 500, such as sheet carrier 402. Figure 6A The image shows a probe 302 connected to a sheet 306 approaching a sheet carrier 402.

[0062] Figure 6B The diagram illustrates a scenario where sheet 306 is welded or otherwise attached to sheet carrier 402. Sheet 306 can also be attached to a sample carrier or similar component in a similar manner. During the mounting of sheet 306 to sheet carrier 402, a change in third current flow can be detected. The mounting operation can be verified, at least in part, based on this change in third current flow. For example, an increase in current flow (completion of the current loop) will cause a change in third current flow.

[0063] Figure 6C The diagram illustrates the separation of probe 302 from sheet 306 after the transfer is complete. After confirming that sheet 306 is mounted based on the change in the third current flow, probe 302 can be detached from sheet 306, as follows: Figure 6C As shown. A fourth current flow change can be detected when probe 302 separates from sheet 306. The separation of probe 302 from sheet 306 can be confirmed at least in part based on the fourth current flow change. For example, an interruption of current flow (disconnection of the current loop) will cause a fourth current flow change.

[0064] According to various embodiments, any change in current flow can be associated with a preset threshold. For example, the change in current flow can be the difference between a first current flow value and a second current flow value. A preset threshold can be defined for each difference. When it is determined that the change in current flow is equal to or exceeds the preset threshold, one or more current flow values ​​and / or the determination result can be output to a system processor or similar device to proceed to the next operation, as will be understood by those skilled in the art upon reading this disclosure.

[0065] Figure 7 and Figure 8 Examples of flowcharts 700 and 800 are shown. These flows, and any other flows described herein, are shown in the form of logic flowcharts, where each operation represents a sequence of operations that can be implemented by hardware, computer instructions, or a combination of both. In the context of computer instructions, these operations may represent computer-executable instructions stored on one or more non-transitory computer-readable storage media, which, when executed by one or more processors, perform the operations. Typically, computer-executable instructions include routines, programs, objects, components, data structures, etc., for performing a particular function or implementing a particular data type. The order in which these operations are described is not intended to be limiting, and any number of these operations may be combined in any order and / or in parallel to implement these flows.

[0066] Alternatively, some, any, or all of the processes described herein may be controlled by one or more computer systems configured with specific executable instructions and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more application programs), co-executing on one or more processors, or implemented in hardware, or a combination of both. As mentioned above, the code may be stored on a non-transitory computer-readable storage medium, for example, in the form of a computer program containing multiple instructions executable by one or more processors.

[0067] Figure 7 A flowchart illustrating a method for precisely controlling the extraction and transfer of thin sections. Various embodiments of method 700 (including any modules described herein) can be performed manually, or... Figure 2Executed under the control of the computer system. Method 700 includes various operations for performing slice extraction and transfer according to embodiments of the present disclosure. Method 700 may include more or fewer operations described herein, and each operation may be performed in a configuration different from that described herein. Method 700 may include module 702. Module 702 may include providing a substrate in an electron microscope system, the system including probes for manipulating the substrate to free samples. According to at least some embodiments, the electron microscope system may be a FIB-SEM system as described herein. In other embodiments, the system may be a FIB system, a FIB-SEM system, a FIB-laser system, a FIB-SEM-laser system, etc. The system may include any combination of any embodiments described herein. The term “probe” is used interchangeably herein with nanomanipulator, needle, etc. In at least some embodiments, probe 302 may be an EasyLift nanomanipulator from Thermo Fisher Scientific.

[0068] Module 704 may include applying a current flow between the system's stage and the probe. This current flow can be applied to the entire sample via the system's stage. This current flow may be a reference current flow with a reference current level greater than or equal to 1 pA. When there is no electrical contact between the probe and the sample, the current flow is at the noise level of the measuring device (e.g., about 1 pA). According to some embodiments, the applied current flow level may be between the reference level and 10 mA. In other embodiments, the applied current flow level may be between the reference level and 10 μA. In a further embodiment, the applied current flow level may be between the reference level and 100 nA.

[0069] Module 706 may include detecting a first current flow change related to probe contact with the sample. The first current flow change is the difference between a reference level of current flow and the applied current flow level. According to various embodiments, module 706 may also include outputting current flow-related information in any suitable manner so that this information can be used as input to a control system. For example, a current reading may be output at preset time intervals (e.g., every 5 seconds, every 10 seconds, every 15 seconds, etc.) so that the control system can determine whether the current reading has changed according to a preset threshold, thereby triggering changes in other parts of the system. For example, the control system may prompt the activation of module 708 based on the input signal provided by module 706.

[0070] Module 708 may include: after detecting a first change in current flow (with the probe already attached to the sheet), removing the last small portion of material connecting the sheet to the whole sample via FIB or laser.

[0071] Module 710 may include detecting a second current flow change associated with sample extraction from the substrate. The second current flow change may indicate that the sample has been disconnected from the substrate, thereby cutting off or interrupting the current loop. The second current flow change is the difference between the applied current level and a reference current level. For example, the second current flow change is a change from an applied current level (e.g., 1 mA) to a noise level of the current flow (e.g., 1 pA). The current change information may be input to a processor or similar device in the system to activate other components of the system and / or to activate module 712.

[0072] Module 712 may include confirmation, at least in part, based on a second current flow change, that the sample has been extracted from the substrate. For example, if the sample is not completely extracted from the substrate, the current flow will not change because the current loop is not broken. In some embodiments, if the sample is not sufficiently separated from the substrate, the current value may not change according to a preset threshold. For example, although the current value may change, the change may not be sufficient to indicate that the sample has been correctly extracted from the substrate. In some embodiments, the extraction result may also be further confirmed based on system imaging or similar methods.

[0073] According to at least some embodiments, method 700 may include recording conditions related to changes in the first and second current flows. Recording the conditions for successful extraction and transfer facilitates the execution of future processes. In some embodiments, these conditions may include pattern size, pattern shape, pattern scanning strategy (e.g., pattern type), beam current, beam energy, pattern depth, patterning time, etc., or any combination thereof. This is particularly useful for training operators performing manual extraction operations. Therefore, parameters of the extraction process (and transfer process) can be efficiently adjusted and applied to subsequent samples. In embodiments of this disclosure where parameters can be confirmed in real time, it is unnecessary to determine the correct parameters for a particular sample through repeated trials.

[0074] Method 700 may also include transferring the sample to other surfaces of the system. For example, the sample may be transferred to a sample holder, sheet carrier, or similar device. Module 714 may include mounting the sample onto a sample carrier of the system using a probe, provided that the sample has been confirmed to have been extracted from the substrate. In at least some embodiments, the same probe may be used to transfer and mount the sample onto the sample carrier. In other embodiments, the sample may be transferred to a different probe before mounting.

[0075] Module 716 may include detecting a third current flow change. When the sample is mounted onto the sample carrier, the current loop is restored, and the current level changes again. For example, the third current flow change is the difference between a reference current flow level and the applied current flow level. The current level may vary from a noise level to the applied current level. In some embodiments, the applied current flow level is less than or equal to 1 mA. In some embodiments, the sample is determined to be correctly mounted only when the change in the current flow value is equal to or greater than a preset threshold difference between the initial current flow value and the current current flow value. For example, mounting the sample may cause a change in the current flow value, but in at least some embodiments, the sample is confirmed to be correctly mounted or the mounting process is considered completely finished only when a preset current flow value (or a preset difference in current flow values) is reached.

[0076] Module 718 may include confirmation that the sample has been mounted, at least in part, based on a change in third current flow. This change in third current flow may indicate that the sample has been correctly soldered or attached to the sample carrier. Confirmation of sample mounting may also be based on image processing or similar methods. Confirmation may be performed, at least in part, based on any of the embodiments described herein.

[0077] Module 720 may include detaching the probe from the sample upon confirmation that the sample has been attached. The probe may be detached from the sample in a manner known in the art. A change in current flow may indicate that the connection between the sample and the probe has been broken, thereby interrupting or breaking the current loop. This change in current flow may be used as input to other components of the system, such as module 722. In some embodiments, the change in current flow may be input to an operating system that guides the probe away from the sample if the sample is broken or otherwise detached from the probe.

[0078] Module 722 may include the detection of a fourth current flow change. When the sample is separated from the probe, the current loop is broken, and the current level changes again. For example, the fourth current flow change is the difference between the current level of the applied current flow and the current level of the reference current flow. The current level may vary from the applied current level to a noise level.

[0079] Module 724 may include confirmation, at least in part, based on a fourth current flow change, that the sample has been separated from the probe. The fourth current flow change may indicate that the sample has been correctly separated from the probe. Confirmation of sample separation may also be based on image processing or similar methods.

[0080] Figure 8A flowchart illustrating a computer-implemented method for precisely controlling the extraction and transfer of thin sections. As described above, each module of method 800 can represent a sequence of operations that can be implemented via hardware, computer instructions, or a combination of both. Module 802 includes, for an electron microscope system, one or more processors of the system controlling the current flow between the stage and the system probe. Module 802 may include applying the current flow as described in module 704 of method 700, as detailed above.

[0081] Method 800 may further include module 804. Module 804 may include detecting a first change in current flow when the sample comes into contact with the probe. When the current flow value reaches or exceeds a preset value, the connection between the sample and the probe is considered sufficiently strong. According to various embodiments, module 804 may also include outputting information related to the current flow in any suitable manner so that the information can be used as input to the control system. For example, a current reading may be output every preset time interval (e.g., every 5 seconds, every 10 seconds, every 15 seconds, etc.) so that the control system can determine whether the current reading has changed according to a preset threshold, thereby triggering changes in other parts of the system.

[0082] Module 806 may include controlling the extraction of a sample from the substrate using a probe upon detection of a first change in current flow. For example, when the difference in the first change in current flow is determined to reach a preset value, the operating system may be activated to control the probe, thereby removing the sample from the substrate. After detecting the first change in current flow (the probe is attached to the sheet), the last small portion of material connecting the sheet to the overall sample may be removed by FIB or laser.

[0083] Module 808 may include detecting a second current flow change associated with the extraction of a sample from the substrate. This second current flow change may indicate that the sample has been successfully separated from the substrate. For example, complete separation of the sample from the substrate would interrupt the current loop and cause the current flow and current value detected by the system to cease.

[0084] Module 810 may include confirmation, at least in part, that the sample has been extracted from the substrate based on a second current flow change. For example, a decrease in current flow (breaking the current loop) will cause a second current flow change. Therefore, the detected current flow change can provide clear quantitative and qualitative information about the integrity of contact and extraction for the system automation process.

[0085] Various embodiments of this disclosure enable precise control over processes such as nanomanipulator-sheet joining, sheet extraction from the whole sample, sheet-mesh joining, and sheet cutting from the nanomanipulator. The provided contact detection function improves system robustness through precise control of each step of the extraction process. Furthermore, embodiments of this disclosure achieve faster parameter tuning for automated tasks by adjusting the pattern depth based on measured current values, thereby increasing system throughput. For example, fewer iterations are required to determine the optimal conditions for the extraction and transfer process for new sheet types or different samples.

[0086] In at least some embodiments, the system configuration described herein may include a dual-beam system equipped with a 110mm or 150mm, 6-inch stage. This system may include an arbitrary five-axis (e.g., X, Y, Z, rotation, tilt) stage of any type of motor (e.g., piezoelectric or stepper motor). A current change of 12nA can be stably and repeatedly detected for each step of the process. Those skilled in the art will understand that all types of stages and sample holders can be used in such a system configuration.

[0087] Electrical contact detection provides clear information about the connection between the nanomanipulator and the TEM sheet at all stages of TEM sheet extraction. This real-time information offers numerous benefits, including: improved success rates in manual TEM sheet preparation processes, faster training of new operators, increased time efficiency of TEM preparation tasks (e.g., adjusting pattern depth based on current flow measurements), improved success rates in automated TEM preparation tasks, more reliable and efficient management of probes between automated TEM preparation tasks, and faster workflow adjustments for automated TEM preparation tasks.

[0088] Another advantage of this disclosure is that the extraction control can provide information for investigating potential failures in automated tasks. For example, information about contact detection can help determine at which stage of the extraction process the error occurred.

[0089] The various embodiments of this disclosure can be implemented using control logic of hardware circuitry (e.g., application-specific integrated circuits (ASICs) or field-programmable gate arrays (FPGAs), and / or implemented in a modular or integrated manner using computer software stored in memory in conjunction with a general-purpose programmable processor. Therefore, the processor may include memory storing software instructions (for configuring the hardware circuitry), and an FPGA or ASIC with configuration instructions. In this document, the processor may include a single-core processor, a multi-core processor on the same integrated chip, multiple processing units on a single circuit board, or multiple processing units connected via a network, as well as dedicated hardware. Based on the disclosure and teachings provided herein, those skilled in the art will know and understand other ways and / or methods of implementing embodiments of this disclosure using hardware and combinations of hardware and software.

[0090] Any software component or function described in this application can be implemented as software code, using any suitable computer language, such as Java, C, C++, C#, Objective-C, Swift, or a scripting language such as Perl or Python, and executed by a processor using, for example, conventional or object-oriented techniques. The software code can be stored as a set of instructions or commands on a computer-readable medium for storage and / or transmission. Suitable non-volatile computer-readable media may include random access memory (RAM), read-only memory (ROM), magnetic media (such as hard disks or floppy disks) or optical media (such as optical discs (CDs) or DVDs (Digital Versatile Optical Discs) or Blu-ray discs), flash memory, etc. The computer-readable medium can be any combination of such devices. Furthermore, the order of operations can be rearranged. A process can terminate upon completion of its operations, but may also have additional modules not included in the accompanying drawings. A process can correspond to a method, function, procedure, subroutine, subroutine, etc. When a process corresponds to a function, its termination can correspond to the function returning to the calling function or the main function.

[0091] Such programs can also be encoded and transmitted using carrier signals adapted for transmission over wired, fiber optic, and / or wireless networks conforming to various protocols, including the Internet. Therefore, computer-readable media containing such programs can be created using data signals. Computer-readable media encoded with program code can be packaged with compatible devices or provided separately from other devices (e.g., downloaded via the Internet). Any such computer-readable media can reside on or within a single computer product (such as a hard drive, CD, or an entire computer system) and can exist on or within different computer products within a system or network. A computer system may include a monitor, printer, or other suitable display for providing a user with any of the results mentioned herein.

[0092] Any method described herein can be performed, wholly or partially, by a computer system including one or more processors configured to execute these modules. Any operation performed by the processor (e.g., alignment, determination, comparison, computation) can be performed in real time. The term "real time" can refer to a computational operation or process completed within a certain time limit. The time limit can be 1 minute, 1 hour, 1 day, or 7 days. Therefore, embodiments of this disclosure are oriented toward computer systems configured to execute various modules of any method described herein, with different components executing corresponding modules or a corresponding set of modules. Although the methods are presented as numbered modules, the method modules herein can be executed simultaneously or at different times, or in different orders. Furthermore, portions of these modules can be combined with portions of modules of other methods. And, all or part of the modules can be optional. Furthermore, any step of any method can be performed by modules, units, circuits, or other means in a system that executes these steps. Furthermore, any module of any method can be executed by modules, units, circuits, or other means in a system.

[0093] In the foregoing specification, embodiments of this disclosure have been described in conjunction with numerous specific details, which may vary in different implementations. The description and accompanying drawings are to be regarded as illustrative and not restrictive. The unique and exclusive indication of the scope of this disclosure, and what the applicant intends to be the scope of this disclosure, is the literal and equivalent scope of the claims granted in the specific form (including any subsequent amendments) published in this application. Specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of this disclosure.

[0094] Furthermore, spatially relative terms (such as "bottom" or "top") may be used to describe the relative relationship of an element and / or feature to other elements and / or features, as illustrated in the accompanying drawings. It should be understood that, in addition to the orientations depicted in the drawings, spatially relative terms are also intended to cover different orientations of the device during use and / or operation. For example, if the device in the drawings is flipped, the element described as the "bottom" surface may be oriented "above" other elements or features. The device may be oriented in other ways (e.g., rotated 90° or in other orientations), and the spatially relative descriptors used herein may therefore be interpreted.

[0095] The terms “and,” “or,” and “and / or” as used herein can have a variety of meanings, which depend at least in part on the context in which they are used. Generally, “or,” when used to relate a series, such as A, B, or C, means A, B, and C, used herein in an inclusive sense, and A, B, or C, used herein in an exclusive sense. Furthermore, the term “one or more,” as used herein, can be used to describe any feature, structure, or property in the singular form, or can be used to describe some combination of features, structures, or properties. However, it should be noted that this is merely an illustrative example, and the claimed subject matter is not limited to this example. Additionally, the term “at least one,” when used to relate a series, such as A, B, or C, can be interpreted as meaning any combination of A, B, and / or C, such as A, B, C, AB, AC, BC, AA, AAB, ABC, AABBCCC, etc.

[0096] In this specification, references to "an example," "one example," "some examples," or "exemplary implementation" indicate that a particular feature, structure, or characteristic described in connection with that feature and / or example may be included in at least one feature and / or example of the claimed subject matter. Therefore, the phrases "in one example," "one example," "some examples," "in some implementations," or other similar phrases used throughout this specification do not necessarily refer to the same feature, example, and / or limitation. Furthermore, a particular feature, structure, or characteristic may be combined in one or more examples and / or features.

[0097] In some implementations, operation or processing may involve the physical manipulation of physical quantities. Generally, although not always, such quantities may take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, and further manipulated. It has proven convenient, primarily for common reasons, to refer to such signals as bits, data, values, elements, symbols, characters, terms, numbers, numerals, etc. However, it should be understood that all such terms or similar terms are associated with the appropriate physical quantity and are merely convenient designations. Unless otherwise expressly stated, as will be apparent from the discussion herein, it should be understood that throughout this specification, discussions using terms such as “processing,” “calculation,” “operation,” “determination,” etc., refer to the actions or processes of a particular device such as a dedicated computer, dedicated computing device, or similar dedicated electronic computing device. Thus, in the context of this specification, a dedicated computer or similar dedicated electronic computing device is capable of manipulating or transforming signals that are generally reproduced as physical electronic or magnetic quantities in the memory, registers, or other information storage devices, transmission devices, or display devices of the dedicated computer or similar dedicated electronic computing device.

[0098] In the foregoing detailed description, numerous specific details have been set forth to provide a full understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter can be practiced without these specific details. In other instances, methods and apparatus known to those of ordinary skill in the art have not been described in detail to avoid obscuring the claimed subject matter. Therefore, the claimed subject matter is not limited to the specific examples disclosed, but may also include all aspects falling within the scope of the appended claims and their equivalents.

Claims

1. A sample preparation method for electron microscopy imaging, comprising: An electron microscope system is provided with a substrate, the system including probes for manipulating the substrate to detach a sample; A current flows between the stage and the probe of the system; Detect the first current flow change associated with probe contact with the sample; After detecting the first change in current flow, a probe is used to extract the sample from the substrate; Detect the second current flow change associated with sample extraction from the substrate; as well as The sample was confirmed to have been extracted from the substrate, at least in part, based on the change in the second current flow.

2. The method according to claim 1, further comprising: Once it is confirmed that the sample has been extracted from the substrate, a probe is used to mount the sample onto the system's sample carrier. Detect changes in the flow of the third current; as well as The instruction to confirm sample installation is based at least in part on changes in the flow of a third current.

3. The method according to claim 2, further comprising: Once it is confirmed that the sample has been installed, detach the probe from the sample; Detect changes in the flow of the fourth current; as well as The separation of the sample from the probe was confirmed at least in part based on the fourth current flow change.

4. The method of claim 1, wherein the current level of the applied current flow is between a reference level and 1 mA.

5. The method of claim 4, wherein the first current flow change is the difference between a reference level of current flow and the current level of the applied current flow.

6. The method of claim 4, wherein the second current flow change is the difference between the applied current flow level and the reference level of the current flow.

7. The method according to claim 1, further comprising: Record the conditions related to the changes in the first and second current flows.

8. The method of claim 7, wherein the conditions include one or more of pattern depth and pattern time.

9. A sample preparation system for electron microscopy imaging, comprising: One ion beam column; One electron beam column; A stage for supporting a substrate; One probe; A current source configured to provide current flowing between the probe and the stage; as well as A controller for controlling the operation of the system, the controller including a memory storing computer instructions for: Based on the sample contact between the probe and the substrate, the current flow between the probe and the stage is detected. move; When current flow is detected, the sample is separated from the substrate using an ion beam; Detect changes in current flow associated with sample extraction from a substrate; as well as The sample was confirmed to have been extracted from the substrate, at least in part, based on changes in current flow.

10. The system of claim 9, wherein the current level of the applied current flow is between a reference level and 1 mA.

11. The system of claim 10, wherein the change in current flow is the difference between a reference level of current flow and the current level of the applied current flow.

12. The system of claim 9, further comprising: Instructions for recording conditions related to changes in current flow.

13. The system of claim 12, wherein the conditions include one or more of pattern depth and pattern time.

14. A non-transitory computer-readable medium storing instructions executable by one or more processors of an electron microscope system, comprising operations performed by the one or more processors including: Current flow between the stage and the probe in the control system; The change in the first current flow is detected when the probe contacts the sample; Upon detecting a change in the first current flow, the control probe extracts the sample from the substrate; Detect the second current flow change associated with sample extraction from the substrate; as well as The sample was confirmed to have been extracted from the substrate, at least in part, based on the change in the second current flow.

15. The non-transitory computer-readable medium of claim 14, further comprising: Once it is confirmed that the sample has been extracted from the substrate, the control probe is instructed to mount the sample onto a surface of the system. Detecting changes in the flow of the third current; and The instruction to confirm sample installation is based at least in part on changes in the flow of a third current.

16. The non-transitory computer-readable medium of claim 14, wherein the current level of the applied current flow is between a reference level and 1 mA.

17. The non-transient computer-readable medium of claim 16, wherein the first current flow change is the difference between a reference level of current flow and the current level of the applied current flow.

18. The non-transient computer-readable medium of claim 16, wherein the second current flow change is the difference between the applied current flow level and a reference level of current flow.

19. The non-transitory computer-readable medium of claim 16, further comprising: Instructions to record processing conditions related to changes in the first and second current flows.

20. The non-transitory computer-readable medium of claim 19, wherein the condition includes one or more of pattern depth and pattern time.

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