Shape-invariant method for accurate benchmark finding

Abstract

Reference coordinates are obtained by aligning a template with a region of interest extracted from a workpiece image. Image values ​​from the region of interest are projected along the template axis, and the projected values ​​are evaluated to establish a reference position, which can be used as a reference location for locating workpiece areas for ion beam milling or other processes.

Description

Technical Field

[0001] This disclosure relates to workpiece alignment using a reference. Background Technology

[0002] Various procedures in the fabrication and evaluation of semiconductors and other devices require determining the precise coordinates of any region of interest on the device. To aid in locating the selected region, the device and its substrate are provided with references that allow for substrate alignment. These references typically contain features intended for orienting the substrate relative to orthogonal linear axes (i.e., the X and Y axes) and, in some cases, for angular alignment relative to these axes.

[0003] In some applications, multiple regions of interest (ROIs) must be located, and reference datums adjacent to these regions must be identified and used for location lookup. An operator may place the substrate within the imaging system's field of view and establish coordinates using the edges defined by the reference datums. This operator intervention can be time-consuming and error-prone. Typically, the operator may be required to locate the reference datum, obtain multiple images of the workpiece, and place reference markers relative to the reference datum to determine precise location before additional image processing. Reference datums of different shapes often require different processing methods, which can be time-consuming and error-prone. Alternative methods are needed, especially those that reduce the need for operator intervention. Summary of the Invention

[0004] The method includes obtaining an image of a workpiece at a first resolution and identifying a workpiece reference in the image, and selecting a portion of the workpiece image containing the workpiece reference as a region of interest (ROI) image at the first resolution. The ROI image is processed to have a second resolution greater than the first resolution. The ROI image is masked using a template based on the workpiece reference, and the ROI image is processed after masking to establish at least one workpiece coordinate associated with the workpiece reference. In some instances, the template is a binary template, and the at least one workpiece coordinate is established by projecting image values ​​along at least one template axis and processing the projected image values.

[0005] A dual charged particle beam (CPB) system includes: an electron microscope column positioned to generate an image of a workpiece; an ion beam column positioned to process the workpiece with an ion beam; and a memory device coupled to store at least one template associated with a workpiece reference design. A processor is coupled to: select a portion of the workpiece reference image as a region of interest (ROI) image at a first resolution; process the ROI image to have a second resolution greater than the first resolution; mask the ROI image with the template based on the workpiece reference; and process the masked ROI image to establish at least one workpiece coordinate associated with the workpiece reference. The processor may be further configured to guide the ion beam to a workpiece location based on the at least one workpiece coordinate to process the selected workpiece region based on the established workpiece coordinates, for example, ion beam milling of the workpiece. In some instances, the at least one template is a binary template.

[0006] The alignment system includes: an imaging device positioned to acquire an image of a workpiece; and a processor coupled to receive the image of the workpiece and establish a reference position on the workpiece by: aligning a binary template with a region of interest in the image; projecting image values ​​from at least a portion of the region of interest along a direction associated with the aligned template; and processing the projected image values.

[0007] The foregoing and other objectives, features, and advantages of the disclosed technology will become more apparent from the following detailed description with reference to the accompanying drawings. Attached Figure Description

[0008] Figure 1 This illustrates a dual-beam system implementing a template-based reference position.

[0009] Figure 2 A representative method for showing the reference position.

[0010] Figures 3A-3B It is an image of the workpiece showing the reference position based on the template.

[0011] Figure 4A It is a schematic diagram of a workpiece image containing a reference image within a region of interest (ROI).

[0012] Figure 4B Show Figure 4A A magnified image of the ROI shown.

[0013] Figure 4C This shows a template corresponding to the baseline image in the magnified ROI image.

[0014] Figure 4D This shows the alignment of the template with a magnified image of the ROI.

[0015] Figure 4EThe diagram shows a representative projection of the image values ​​and a curve fit to the projected image values.

[0016] Figures 5A-5B An additional template is shown for the reference position.

[0017] Figure 6 A representative method for evaluating workpieces with patterned deformation is shown.

[0018] Figure 7 It is a block diagram of a representative processing system for template-based reference locations. Detailed Implementation

[0019] Introduction and Terminology

[0020] This document discloses a method and apparatus for datum position detection using the positioning of a template pattern. Typically, a single workpiece image is acquired and a template pattern is used with an image portion containing a datum image. The aligned template pattern can be used to select image values ​​projected along the template axis. The projected values ​​extend across the ROI image portion associated with the datum and can be processed by curve fitting or other procedures to position the datum. The selection of the ROI image portion can eliminate or reduce the influence of out-of-area artifacts and allows the datum to be positioned without operator intervention. If a different datum design is to be used, a corresponding template pattern can be provided, but the processing remains substantially unchanged in other respects and generally does not require additional customization.

[0021] As used herein, “image” means a visual presentation intended for viewing on a display device, such as a projection onto a surface like a projection screen, or otherwise presented for viewing by a technician, operator, or other person. “Image” also refers to a digital representation of a viewable image in an image file such as JPG, TIFF, BMP, or other formats. Such digital representations contain or can be processed to produce an intensity value I(x,y) as a function of position, where x and y are coordinates along linearly independent (and generally orthogonal) axes. In the examples described herein, intensity is presented as a single value without reference to the color the observer will be viewing. However, in some cases, intensity values ​​associated with more spectral components (e.g., red, green, and blue) or other image values ​​(e.g., hue, saturation, and value) or color coordinates (e.g., LAB, CYMK, RGB) may be used. In many practical instances, the image of interest is a charged particle beam (CPB) image, and a single intensity value is appropriate.

[0022] In the examples described below, a single image of the workpiece or a portion thereof is obtained at a first resolution, and the image portion containing the reference (region of interest or ROI) is selected and magnified to provide an ROI associated with a second resolution greater than the first resolution. As used herein, image resolution is associated with image pixel size. A first image with fewer pixels associated with the workpiece size than the second image is referred to as “higher resolution.” In a typical example, the first image (of a relatively large workpiece area) at the first resolution is processed to obtain an image portion associated with the ROI, i.e., the ROI image portion or the ROI image. The ROI image portion can be scaled such that the pixels in the ROI image correspond to a smaller workpiece size, and the ROI image can be referred to as having a higher resolution than the first image. In some instances, images with pixel sizes of 50, 25, 10, or 5 nm are obtained, and the associated ROI images have pixel sizes of 10, 5, 2, or 1 nm, respectively, but other resolutions and scaling can be used. For example, the ROI can be scaled by factors of 2, 4, 5, 10, 15, 20, or other factors. Selecting a ROI from the first image allows for a baseline location based on a single image, which can be faster and requires less operator intervention.

[0023] These examples are shown as visual images in some figures, but the operations performed typically do not require operator intervention or viewing of the image. For example, a template corresponding to a reference is shown as having transmissive or non-transmissive portions, but this involves how the template can be applied to the image data and does not require visual inspection.

[0024] For convenience, the disclosed template is shown as a binary mask having a transmissive area and an opaque area forming the template pattern, and is simply referred to herein as the "template".

[0025] Example 1

[0026] refer to Figure 1In a representative embodiment, the dual-beam system 100 includes a scanning electron microscope (SEM) 102 and an ion beam column 104. The SEM 102 may include one or more charged particle beam (CPB) lenses, such as a condenser lens 116 and an objective lens 106. In some embodiments, the one or more CPB lenses may be magnetic lenses, and specifically, the objective lens 106 may be a magnetic objective lens. The ion beam column 104 is arranged to provide a focused ion beam (FIB) to a sample S, and the SEM 102 is positioned to produce an image of the sample S. The SEM 102 and the ion beam column 104 may be mounted to a vacuum chamber 108, which houses a movable substrate holder 110 for holding the sample S. The vacuum chamber 108 may be evacuated using a vacuum pump (not shown). The substrate holder 110 may be movable in an XY plane as shown relative to coordinate system 150, where the Y-axis is perpendicular to the image plane. The substrate holder 110 may be further moved vertically (along the Z-axis) to compensate for variations in the height of the sample S. In some embodiments, the SEM 102 may be vertically arranged above the sample S and may be used to image the sample S, and the ion beam column 104 may be arranged at an angle and may be used to process and / or treat the sample S. Figure 1 An exemplary orientation of the SEM 102 and ion beam column 104 is shown. In some instances, the substrate holder may be tilted such that an electron beam, such as an SEM electron beam or an ion beam, such as a focused ion beam (FIB), can be applied from vertically below the sample for various milling or imaging operations.

[0027] SEM 102 may include an electron source 112 and may be configured to manipulate the “raw” radiation beam from the electron source 112 and perform operations such as focusing, aberration reduction, cropping (using an aperture), filtering, etc. SEM 102 may generate an input beam of charged particles 114 (e.g., an electron beam) propagating along a particle optical axis 115. SEM 102 typically includes one or more lenses (e.g., CPB lenses) for focusing the beam 114 onto a sample S, such as a condenser lens 116 and an objective lens 106. In some embodiments, SEM 102 may be provided with a deflection unit 118 that can be configured to manipulate the beam 114. For example, the beam 114 may be manipulated across the sample under study using scanning motion (e.g., raster or vector scan).

[0028] The dual-beam system 100 may further include a computer processing unit and / or a control unit 128 for controlling, in particular, the deflection unit 118, the charged particle beam (CPB) lenses 106, 116, and the detector (not shown), and for displaying information collected from the detector on a display unit. The control unit 128 may also control the ion beam 124 to remove material from selected areas of the sample S by milling or otherwise processing the sample S. In some cases, the control computer 130 is configured to establish various excitations, control FIB milling, locate references before or after ion beam milling operations and align the sample S with these references, record imaging data, and typically control the operation of both the SEM 102 and the ion beam column 104.

[0029] Still referencing Figure 1 The ion beam post 104 may include an ion source (e.g., a plasma source 120) and an ion beam optics device 122. In the illustrated embodiment, the ion beam post 104 is a plasma focused ion beam (PFIB); however, in other embodiments, the ion beam post 104 may be a standard focused ion beam (FIB) with a liquid metal ion source (LMIS) or any other ion source compatible with a focused ion beam post. The ion beam post 104 may generate and / or guide the ion beam 124 along the ion optical axis 125. As described above, the ion post 104 can be used to perform imaging, processing, and / or fabrication operations on a substrate, such as cutting, milling, etching, deposition, etc.

[0030] In embodiments where the ion beam is a PFIB, the ion source 120 can be fluidly coupled to multiple gases via a gas manifold 126, which includes gas sources 142A-142D coupled to the ion source 120 via corresponding valves 141A-141D. Valve 140 is positioned to selectively couple gas from the gas manifold 126 to the ion source 120. Figure 1 As shown, exemplary gases include, but are not limited to, xenon, argon, oxygen, and nitrogen. During operation of the ion source 120, a gas may be introduced, which becomes charged or ionized, thereby forming a plasma. Ions extracted from the plasma can then be accelerated through the ion beam column 104, thus becoming an ion beam. While ion beam milling is a typical application, ion beam-assisted material deposition can also be performed using the dual-beam system 100. The gas delivery system may be coupled to expose the surface of the sample S to a suitable gas, typically a precursor gas composed of organometallic molecules, via a gas inlet. A reference position may be determined using a control computer 130. In some instances, the substrate is shielded and / or referenced before being introduced into the dual-beam system 100.

[0031] A template for determining reference coordinates can be stored in processor-readable storage device 129 and transmitted to control computer 130 and / or control unit 128. As indicated, the template can be received via a network such as a local area network (LAN) or wide area network (WAN). Additionally, one or both of control computer 130 and control unit 128 can receive processor-executable instructions for determining reference coordinates using the template. These instructions can be stored in a suitable local memory device or remotely stored and transmitted via LAN or WAN.

[0032] Example 2

[0033] The method used to establish reference positions Figure 2 As shown in -3. Reference Figure 2 Representative method 200 includes receiving a reference template at 202 or retrieving a reference template from a processor-readable storage device. At 204, an image of the workpiece is obtained at a first resolution. At 206, a reference is located in the image and a corresponding region of interest (ROI) is selected with respect to the reference. Although the image may contain one or more reference images, the reference closest to the feature of interest on the workpiece or another reference that may be convenient can be selected. At 208, the ROI is magnified to produce an ROI image at a second resolution greater than the first resolution. The selected template, ROI, and magnification are chosen such that the template size corresponds to the reference image in the magnified ROI image. In the ROI image, the pixel size is typically 4, 8, 16, or more times smaller than in the first resolution image. At 210, the template is aligned with the reference image in the magnified ROI by, for example, correlation. At 212, a local ROI is selected based on the aligned template. If necessary, an edge-finding procedure, such as Sobel edge lookup, can be performed at 214 to locate the reference edges and generate an edge map. At 216, the local ROI (or edge map) can be projected along the template axis. This projection typically combines the local ROI image data along the template axis and increases the signal-to-noise ratio. At 218, the obtained one-dimensional profile (projected local ROI image data as a function of position transverse to the template axis) can be processed to establish a reference position. Reference edges, midpoints, or other features can be used. At 220, the workpiece region is located based on the established reference position. Typically, the relative coordinates of workpiece features can be obtained based on the workpiece design, and the establishment of the reference position (coordinates) allows the workpiece to move (translate or rotate) to the selected processing area or the processing beam to deflect to the selected processing area. At 220, the selected workpiece region (or multiple regions) is processed by, for example, FIB milling. In other instances, inspection, measurement, material deposition, patterning, or other operations are performed. At 222, it is determined whether additional reference positions need to be established. If so, the processing can return to 202, but in some instances, the same template and / or the same workpiece image are reused, and the processing can return to 204 or 206.

[0034] Example 3

[0035] Figure 3A A workpiece image 302 is shown, containing a representative reference image 304. The region of interest 306 of image 302, which includes reference 304, is shown in... Figure 3B The image is magnified. Template 310, containing orifices 312, 313 and 314, 315, is shown aligned with reference 304; for clarity, the outline of template 310 is shown. Typically, template 310 is a binary template, which is translucent at orifices 312-315 and opaque elsewhere. However, a template with partially translucent areas can be used in addition to, or in place of, completely opaque and translucent areas. As shown, the template and ROI image are selected such that the template features (orifices) and the reference image portion have corresponding dimensions. The ROI magnification can be changed to match the template, or the template can be changed to match the reference dimensions in the ROI image, or both.

[0036] Example 4

[0037] Figures 4A-4E The method described above is shown, but the processing for matching template features and reference dimensions (if needed) is not shown. Figure 4A This is a schematic representation of a workpiece image 400, which includes a representative reference 401 comprising vertical stripes 402, 404. For convenience, the workpiece image 400 is shown as an array of rectangular pixels divided into, for example, representative pixels 404, where each pixel is associated with an image intensity and coordinates, i.e., I(x,y). The array extends a total distance ΔX and ΔY along orthogonal X and Y axes, respectively. A Region of Interest (ROI) image 406 can be selected from the workpiece image 400, and the ROI image can be enlarged to produce... Figure 4B The magnified ROI image 408 is shown. The ROI image 408 has a relative magnification M relative to the workpiece image 400, and has a total X range ΔX' and a Y range ΔY', respectively, wherein the pixel size is M times smaller than that in the workpiece image 400. Figure 4C A template 410 is shown containing orifices 412 and 413, the sizes of which are set to correspond to features 402 and 403 of the template 410 having a magnification M. Figure 4D In the image, template 410 is shown as being superimposed on ROI image 408 and aligned such that apertures 412 and 413 are located at template features 402 and 403, respectively.

[0038] To locate the reference point and provide reference coordinates, the image values ​​(typically intensity) associated with pixels in the ROI image can be summed along the direction indicated by arrows 420 and 422 (Y direction) to provide the projected intensity I as a function of distance along the X-axis. P, that is, I P (X). As used herein, combining in this manner along an axis defined by the template is referred to as projecting intensity values ​​along the template axis. The template axis is generally oriented in a direction different from (e.g., orthogonal) to the direction along which it will determine the template position or template coordinates. The intensity values ​​are combined along the indicated direction, typically in conjunction with region 411, which may be smaller than the ROI image 408 and may contain only the intensity associated with the transmissive portion of the template or also with the non-transmissive portion. If desired, the resulting projected intensity I can be scaled. P (X), or a sum without scaling can be used. A representative example is... Figure 4E The curve is shown in the graph. The projected intensity 430 is shown together with the curve fit 432, which allows for a good position of the X-coordinate associated with the peaks 434, 436 and the midpoint 438 between the peaks. While the X-coordinate associated with the peaks can be used to establish a reference coordinate system, it is sometimes better to use the X-coordinate associated with the midpoint or minimum value. As shown, the reference is determined to be at the point where the X-coordinate X... F The associated location.

[0039] exist Figures 4A-4E In this example, only the X coordinates associated with the datum are obtained, and the template used is selected to provide the X position. Additional template features, such as... Figures 3A-3B The template features shown are typically adapted for determining the X and Y coordinates through processing as described in the related description. The known reference coordinates then allow for processing or evaluation of specific workpiece areas.

[0040] Example 5

[0041] Figures 5A-5B Additional instances of templates used for reference positions are shown. (Reference) Figure 5AA representative template 500 includes a non-transmissive region 502 defining a transmissive ring 504. The template 500 can be aligned with a reference image using correlation or other techniques. Image data can be projected within an image region 508, which extends along a template axis 512 and may have a width transverse to the template axis 512, the width corresponding to one, several, or many pixels. Image data can be projected along, for example, a circumferential axis or a linear axis 506 to provide projected data, the projected data being a function of a position transverse to the template axis 512. Image data can also be similarly projected within an image region 510, which extends along a template axis 514 and may have a width transverse to the template axis 514, the width corresponding to one, several, or many pixels. ROI image data within the image region 510 can be projected along, for example, a circumferential axis 516 to provide projected data, the projected data being a function of a position transverse to the template axis 514. As shown in the figure, template axes 512 and 514 do not need to be orthogonal or parallel to the coordinate axes of the XY coordinate system 520. In this example, template axes 512 and 514 are inclined relative to coordinate axis 520. ROI image data associated with image regions 508 and 510 can be processed to determine reference positions along axes 512 and 514, respectively. These positions can be used to determine reference X and Y coordinates. Axes 512 and 514 do not need to be orthogonal, and any non-parallel axes can be used, although orthogonal or nearly orthogonal axes generally provide better results.

[0042] refer to Figure 5B Representative template 521 includes transmission slit groups 526 and 528 in opaque area 522. Image data associated with image portions near groups 526 and 528 can be projected along corresponding axes 534 and 548 into image regions 544 and 548 to provide projected image data, which is a function of position along corresponding axes 554 and 556. Evaluation of accumulated image data allows determination of reference coordinates along axes 554 and 556, which can be converted into X and Y coordinates.

[0043] Example 6

[0044] refer to Figure 6 Method 600 includes, in 602, using a template based on a reference shape to establish the positions of two or more references as described above. In 604, a reference separation based on the workpiece design is obtained, and in 606, workpiece pattern deformation can be determined by comparing the measured reference separation with the designed separation. In another instance, three or more references can be positioned to determine workpiece rotation.

[0045] Example 7

[0046] Figure 7 The following discussion is intended to provide a brief overview of exemplary computing environments in which the disclosed techniques can be implemented. Although not required, the techniques of this disclosure are described in the general context of computer-executable instructions (such as program modules) executed by a personal computer (PC). Typically, program modules contain routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. Furthermore, the disclosed techniques can be implemented using other computer system configurations including handheld devices, multiprocessor systems, microprocessor-based or programmable consumer electronics devices, network PCs, microcomputers, mainframes, etc. The disclosed techniques can also be practiced in distributed computing environments where tasks are performed on remote processing devices linked via a communication network. In a distributed computing environment, program modules can reside on both local memory storage devices and remote memory storage devices.

[0047] refer to Figure 7 An exemplary system for implementing the disclosed technology includes a general-purpose computing device in the form of an exemplary conventional PC 700, the general-purpose computing device including one or more processing units 702, system memory 704, and a system bus 706 coupling various system components including the system memory 704 to the one or more processing units 702. The system bus 706 may be any of several types of bus structures using any of a variety of bus architectures, including a memory bus or memory controller, a peripheral bus, and a local bus. The exemplary system memory 704 includes read-only memory (ROM) 708 and random access memory (RAM) 710. A basic input / output system (BIOS) 712 is stored in the ROM 708, the BIOS containing basic routines that facilitate the transfer of information between components within the PC 700. The memory 704 also includes portions 771-773, which respectively contain template data, computer-executable instructions for image processing such as magnification, template application, ROI selection, and image data accumulation, and instructions for cumulative image data processing including curve fitting and extraction of reference coordinates, coordinate transformation, and determination of workpiece rotation and deformation.

[0048] The exemplary PC 700 further includes one or more storage devices 730, such as a hard disk drive for reading from and writing to a hard disk, a disk drive for reading from or writing to a removable disk, and an optical disc drive for reading from or writing to a removable optical disc (e.g., a CD-ROM or other optical media). Such storage devices may be connected to the system bus 706 via a hard disk drive interface, a disk drive interface, and an optical disc drive interface, respectively. The drives and their associated computer-readable media provide the PC 700 with non-volatile storage of computer-readable instructions, data structures, program modules, and other data. Other types of computer-readable media that can store data accessible by the PC, such as magnetic tape cartridges, flash memory cards, digital video optical discs, CDs, DVDs, RAM, ROM, etc., may also be used in the exemplary operating environment.

[0049] Multiple program modules may be stored in storage device 730, which includes: operating system, one or more applications, other program modules, and program data. Users can input commands and information to PC 700 via one or more input devices 740, such as a keyboard, and a pointing device, such as a mouse. Other input devices may include digital cameras, microphones, joysticks, gamepads, satellite dish antennas, scanners, etc. These and other input devices are typically connected to one or more processing units 702 via a serial port interface coupled to system bus 706, but may also be connected via other interfaces such as parallel ports, game ports, or Universal Serial Bus (USB). Monitor 746 or other types of display devices are also connected to system bus 706 via an interface such as a video adapter. Other peripheral output devices may be included, such as speakers and printers (not shown).

[0050] PC 700 can operate in a networked environment using a logical connection to one or more remote computers, such as remote computer 760. In some instances, it includes one or more network or communication connections 750. Remote computer 760 may be another PC, server, router, network PC, or peer device, or other common network node, and typically includes many or all of the elements described above with respect to PC 700, although... Figure 7 Only the memory storage device 762 is shown. The personal computer 700 and / or remote computer 760 can be connected to a logical local area network (LAN) and a wide area network (WAN). Such network environments are common in offices, enterprise-wide computer networks, intranets, and the Internet.

[0051] When used in a LAN networking environment, PC 700 connects to the LAN via a network interface. When used in a WAN networking environment, PC 700 typically includes a modem or other devices for establishing communication over a WAN, such as the Internet. In a networked environment, program modules or portions thereof depicted relative to PC 700 may be stored in remote storage devices or other locations on the LAN or WAN. The network connections shown are exemplary, and other devices for establishing communication links between computers may be used.

[0052] Representative Examples

[0053] Example 1 is a method comprising: obtaining an image of a workpiece at a first resolution and identifying a workpiece reference in the image; selecting a portion of the image of the workpiece containing the workpiece reference as a region of interest (ROI) image at the first resolution; processing the ROI image to give the ROI image a second resolution greater than the first resolution; masking the ROI image with a template based on the workpiece reference; and processing the masked ROI image to establish at least one workpiece coordinate associated with the workpiece reference.

[0054] Example 2 includes the subject matter described in Example 1, and further includes processing the workpiece region based on at least one established workpiece coordinate.

[0055] Example 3 includes the subject matter of any one of Examples 1 to 2, and further specifies that processing the workpiece area includes ion beam milling of the workpiece area.

[0056] Example 4 includes the subject matter of any one of Examples 1 to 3, and further specifies that the template is a binary template.

[0057] Example 5 includes the subject matter of any one of Examples 1 to 4, and further specifies that at least one workpiece coordinate includes at least one of a first coordinate and a second coordinate along a first axis and a second axis, respectively, wherein the first axis and the second axis are linearly independent axes.

[0058] Example 6 includes the subject matter of any one of Examples 1 to 5, and further specifies that the coordinates of the at least one workpiece are established by identifying the reference edge in the masked ROI image.

[0059] Example 7 includes the subject matter of any one of Examples 1 to 6, and further specifies that the at least one workpiece coordinates are established by projecting image values ​​along at least one template axis and processing the projected image values.

[0060] Example 8 includes the subject matter of any one of Examples 1 to 7, and further specifies that the projected image value is a function of the position along an axis transverse to the template axis, and the at least one coordinate is obtained based on one or more of the maximum or minimum projected image values.

[0061] Example 9 includes the subject matter of any one of Examples 1 to 8, and further specifies that processing the ROI image to give the ROI image a second resolution greater than the first resolution includes enlarging the ROI image to correspond to the template.

[0062] Example 10 includes the subject matter of any one of Examples 1 to 9, and further specifies that processing the ROI image to make the ROI image have a second resolution greater than the first resolution includes enlarging the ROI image to correspond to the template.

[0063] Example 11 includes the subject matter of any one of Examples 1 to 10, and further specifies that masking the ROI image with a template based on the workpiece reference includes enlarging the template based on the reference size in the ROI image.

[0064] Example 12 is a dual charged particle beam (CPB) system comprising: an electron microscope column positioned to generate an image of a workpiece; an ion beam column positioned to process the workpiece with an ion beam; a storage device coupled to store at least one template associated with a workpiece reference design; and a processor coupled to: select a portion of the image of the workpiece, including the workpiece reference image, as a region of interest (ROI) image at a first resolution; process the ROI image to have a second resolution greater than the first resolution; mask the ROI image with the template based on the workpiece reference; and process the masked ROI image to establish at least one workpiece coordinate associated with the workpiece reference.

[0065] Example 13 includes the subject matter described in Example 12, and further specifies that the processor is further configured to guide the ion beam to the workpiece location based on the at least one workpiece coordinate for processing a selected workpiece region based on the established workpiece coordinate.

[0066] Example 14 includes the subject matter of any one of Examples 12 to 13, and further specifies that the ion beam can be used to mill the selected workpiece area.

[0067] Example 15 includes the subject matter of any one of Examples 12 to 14, and further specifies that the at least one workpiece coordinate is a reference coordinate, and the processor is configured to determine at least one coordinate of the workpiece region to be processed based on the reference coordinate.

[0068] Example 16 includes the subject matter of any one of Examples 12 to 15, and further specifies that the at least one template is a binary template.

[0069] Example 17 includes the subject matter of any one of Examples 12 to 16, and further specifies that the processor is configured to establish workpiece coordinates relative to a first linear independent axis and a second linear independent axis based on the masked ROI image.

[0070] Example 18 includes the subject matter of any one of Examples 12 to 17, and further specifies that the processor is configured to establish workpiece coordinates relative to a first linear independent axis and a second linear independent axis based on the masked ROI image.

[0071] Example 19 includes the subject matter of any one of Examples 12 to 18, wherein the processor is configured to establish the workpiece coordinates by identifying reference edges in the masked ROI image.

[0072] Example 20 is an alignment system comprising: an imaging device positioned to acquire an image of a workpiece; and a processor coupled to receive the image of the workpiece and establish a reference position on the workpiece by means of the following steps: aligning a binary template with a region of interest in the image, projecting image values ​​in at least a portion of the region of interest along a direction associated with the aligned template, and processing the projected image values.

[0073] Given the many possible embodiments to which the disclosed technical principles can be applied, it should be recognized that the embodiments shown are merely preferred examples and should not be considered as a limitation of the scope.

Claims

1. A method comprising: Obtain an image of the workpiece at a first resolution and identify the workpiece reference in the image; A portion of the workpiece reference image in the image of the workpiece is selected as the region of interest (ROI) image at the first resolution; The ROI image is processed to have a second resolution greater than the first resolution; The ROI image is masked based on the workpiece reference using a template, the template containing at least one opening; as well as The portion of the masked ROI image within the area defined by the at least one aperture is processed to establish at least one workpiece coordinate associated with the workpiece reference, wherein the at least one workpiece coordinate is determined by summing the image intensity values ​​of the portion of the masked ROI image defined by the at least one aperture along at least one template axis; and processing the sum of the image intensity values ​​to obtain the workpiece coordinate associated with a direction perpendicular to the at least one template axis.

2. The method according to claim 1, further comprising processing the workpiece region based on at least one established workpiece coordinate.

3. The method of claim 2, wherein processing the workpiece region comprises ion beam milling of the workpiece region.

4. The method according to claim 1, wherein the template is a binary template, and the binary template occludes the region in the masked ROI image other than the region defined by the at least one aperture of the template.

5. The method of claim 1, wherein at least one workpiece coordinate comprises at least one of a first coordinate and a second coordinate along a first axis and a second axis, respectively, wherein the first axis and the second axis are linearly independent axes.

6. The method of claim 1, wherein the at least one workpiece coordinate is established by identifying a reference edge in the masked ROI image.

7. The method of claim 1, wherein the summed image intensity values ​​are a function of the position along an axis transverse to the template axis, and the at least one coordinate is obtained based on one or more of the maximum or minimum summed image intensity values.

8. The method of claim 1, wherein the summed image intensity values ​​are a function of the position along an axis transverse to the template axis, and the at least one coordinate is obtained based on the minimum projected image value.

9. The method of claim 1, wherein processing the ROI image to give the ROI image a second resolution greater than the first resolution comprises enlarging the ROI image to correspond to the template.

10. The method of claim 1, wherein masking the ROI image with a template based on the workpiece reference includes enlarging the template based on the reference size in the ROI image.

11. A dual-charged particle beam system, comprising: An electron microscope column, positioned to produce an image of the workpiece at a first resolution; An ion beam column, positioned to treat the workpiece with an ion beam; and A storage device coupled to store at least one template associated with a workpiece reference design; as well as The processor, which is coupled to: A portion of the workpiece reference image in the image of the workpiece is selected as the region of interest (ROI) image at the first resolution; The ROI image is processed to have a second resolution greater than the first resolution; The ROI image is masked based on the workpiece reference using a template, the template containing at least one opening; as well as The portion of the masked ROI image within the area defined by the at least one aperture is processed to establish at least one workpiece coordinate associated with the workpiece reference, wherein the at least one workpiece coordinate is determined by summing the image intensity values ​​of the portion of the masked ROI image defined by the at least one aperture along at least one template axis; and processing the sum of the image intensity values ​​to obtain the workpiece coordinate associated with a direction perpendicular to the at least one template axis.

12. The dual charged particle beam system of claim 11, wherein the processor is further configured to guide the ion beam to the workpiece position based on the at least one workpiece coordinate for processing a selected workpiece region based on the established workpiece coordinate.

13. The dual charged particle beam system of claim 11, wherein the ion beam can be used to mill a selected workpiece region.

14. The dual charged particle beam system of claim 11, wherein the at least one workpiece coordinate is a reference coordinate, and the processor is configured to determine at least one coordinate of the workpiece region to be processed based on the reference coordinate.

15. The dual charged particle beam system according to claim 11, wherein the at least one template is a binary template.

16. The dual charged particle beam system of claim 11, wherein the processor is configured to match the reference and template feature dimensions in the ROI before masking the ROI with a template.

17. The dual charged particle beam system of claim 11, wherein the processor is configured to establish workpiece coordinates relative to a first linear independent axis and a second linear independent axis based on the masked ROI image.

18. The dual charged particle beam system of claim 11, wherein the processor is configured to establish the workpiece coordinates by identifying reference edges in the masked ROI image.

19. An alignment system comprising: An imaging device, positioned to acquire an image of a workpiece; as well as A processor coupled to receive the image of the workpiece and establish at least one workpiece coordinate as a reference for the workpiece by aligning a binary template with a region of interest (ROI) in the image, wherein the at least one workpiece coordinate is determined by summing image intensity values ​​within a region defined by the binary template in the ROI image along at least one template axis; and processing the sum of the image intensity values ​​to obtain the workpiece coordinates associated with a direction perpendicular to the at least one template axis.

Images