Scanning electron microscope image anchoring for array design

Abstract

The scanning electron microscope receives a result file for the wafer from the optical inspection system. The result file includes anchor points on the wafer. A defect review image at the anchor points on the wafer is generated using the scanning electron microscope. The design clip is aligned to the defect review image at the anchor points, thereby generating an aligned defect review image. The aligned defect review image is used for defect detection.

Description

[Technical Field]

[0001] The present disclosure relates generally to semiconductor defect review. [Background technology]

[0002] REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 067,824, filed and assigned on August 19, 2020, the disclosure of which is incorporated herein by reference.

[0003] The evolution of the semiconductor manufacturing industry is placing greater demands on yield management, particularly on metrology and inspection systems. As critical dimensions continue to shrink, the industry must reduce the time to achieve high-yield, high-value production. Minimizing the total time from detecting a yield problem to fixing it determines a semiconductor manufacturer's return on investment.

[0004] Fabricating semiconductor devices, such as logic and memory devices, typically involves processing semiconductor wafers using a number of manufacturing processes to form various features and levels of the semiconductor devices. For example, lithography is a semiconductor manufacturing process that involves transferring a pattern from a reticle to a photoresist disposed on a semiconductor wafer. Further examples of semiconductor manufacturing processes include, but are not limited to, chemical mechanical polishing (CMP), etching, deposition, and ion implantation. Multiple semiconductor devices may be disposed and fabricated on a single semiconductor wafer, which is then separated into individual semiconductor devices.

[0005] Inspection processes are used at various steps during semiconductor manufacturing to detect defects on wafers to promote higher yields, and therefore higher profits, in the manufacturing process, and inspection has always been an important part of manufacturing semiconductor devices such as integrated circuits (ICs). However, as the dimensions of semiconductor devices decrease, inspection becomes even more important to the successful manufacture of semiconductor devices because smaller defects can cause the device to fail. For example, as the dimensions of semiconductor devices shrink, detection of reduced-size defects has become necessary because even relatively small defects can cause undesirable aberrations in the semiconductor device.

[0006] However, as design rules shrink, semiconductor manufacturing processes may be operating closer to the limits of the process's performance capabilities. Additionally, smaller defects may affect device electrical parameters as design rules shrink, driving more sensitive inspection. As design rules shrink, the population of potentially yield-relevant defects detected by inspection increases dramatically, and the population of nuisance defects detected by inspection also increases dramatically. Therefore, more defects may be detected on a wafer, and modifying the process to eliminate all of the defects may be difficult and expensive. By determining which of the defects actually affect the device's electrical parameters and yield, process control methods can be focused on those defects while largely ignoring other defects. Furthermore, with smaller design rules, process-induced failures, in some cases, tend to be systematic. That is, process-induced failures tend to fail in predetermined design patterns that are often repeated multiple times within a design. Eliminating spatially systematic and electrically related defects can impact yield.

[0007] Due to repeating patterns (i.e., cells) in the array region, scanning electron microscope (SEM) tools often do not align images to the design at the target location. Alignment often locks onto the repeating pattern incorrectly, resulting in reports with inaccurate coordinates for defects. The cell size must be larger than the combined uncertainty in the optical inspection system (e.g., a broadband plasma (BBP) tool) and the scanning electron microscope (SEM) stage. For example, the cell size may need to be larger than (250 nm + 125 nm) × 2 = 750 nm for successful alignment at the target location. In this example, 250 nm is for the SEM and 125 nm is for the optical inspection system, but these values ​​may vary depending on the specific system. This value can be either positive or negative, so it is multiplied by 2, and the cell size therefore accounts for it. In many cases, the cell size is smaller than this uncertainty.

[0008] Current technology relies on semiconductor manufacturers to provide design anchor locations. The SEM tool obtains a list of design anchor locations from the semiconductor manufacturer and, for each defect target, finds the closest anchor location. It moves the stage to the anchor location, captures the image and design, performs alignment for the design, and then moves to the target location adjusted by the alignment correction found at the anchor site. However, the SEM tool does not have an automated method for analyzing the design to determine the anchor locations. Semiconductor manufacturers may not provide anchor locations for all layers in a semiconductor device. The semiconductor manufacturer's anchor locations may also require different design layers compared to the target location design layers used for detection. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0228866 [Patent Document 2] U.S. Patent Application Publication No. 2019 / 0362489 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there is a need for improved systems and techniques for semiconductor detection review. [Means for solving the problem]

[0011] In a first embodiment, a method is provided. The method includes, at a scanning electron microscope tool, receiving a results file for a wafer from an optical inspection system. The results file includes anchor points on the wafer. A defect review image is generated at the anchor points on the wafer using the SEM. A design clip is aligned to the defect review image at the anchor points, thereby generating an aligned defect review image. Defects are detected in the aligned defect review image.

[0012] The method can include determining an anchor point using an optical inspection system. The optical inspection system can generate pixel-to-design alignment image patches, and the anchor point can be selected from the pixel-to-design alignment image patches. The anchor point can be selected from the pixel-to-design alignment image patches using a generative adversarial network (GAN). Determining the anchor point can include ranking the pixel-to-design alignment image patches and selecting one of the pixel-to-design alignment image patches as the anchor point.

[0013] The design clip can be a 1 mm x 1 mm area on a die on a wafer.

[0014] The method may include performing precision alignment of the defect review image using targets on the defect review image.

[0015] The aligned defect review image can have a position uncertainty of ±25 nm.

[0016] The detection can be performed in array mode.

[0017] In a second embodiment, a system is provided. The system includes an SEM tool having a stage configured to hold a wafer, an electron source configured to emit electrons toward the wafer, and a detector configured to detect electrons received from the wafer. The system also includes a processor in electronic communication with the SEM configured to receive a results file for the wafer from the optical inspection system. The results file includes anchor points on the wafer. The processor is further configured to generate a defect review image at the anchor points on the wafer, align a design clip to the defect review image at the anchor points, thereby generating an aligned defect review image, and detect defects in the aligned defect review image.

[0018] The system can include an optical inspection system. The optical inspection system can be configured to generate pixel-to-design alignment image patches, and the anchor points can be selected from the pixel-to-design alignment image patches.

[0019] The system can include a GAN unit configured to select anchor points from pixel-to-design aligned image patches.

[0020] The design clip can be a 1 mm x 1 mm area on a die on a wafer.

[0021] The processor may be further configured to perform fine alignment of the defect review image using the targets on the defect review image.

[0022] The aligned defect review image can have a position uncertainty of ±25 nm.

[0023] In a third embodiment, a non-transitory computer-readable storage medium is provided. The computer-readable storage medium includes one or more programs configured to execute the following steps on one or more processors: receiving a result file for a wafer from an optical inspection system, the result file including anchor points on the wafer; generating a defect review image at the anchor points on the wafer; aligning design clips to the defect review image at the anchor points, thereby generating an aligned defect review image; and detecting defects in the aligned defect review image.

[0024] The optical inspection system can be configured to generate pixel-to-design alignment image patches, and the anchor points can be selected from the pixel-to-design alignment image patches.

[0025] Anchor points can be selected from pixel-to-design alignment image patches using GANs.

[0026] The anchor points can be received by the SEM from the optical inspection system via a results file.

[0027] The one or more programs may be further configured to perform precision alignment of the defect review image using targets on the defect review image.

[0028] The aligned defect review image can have a position uncertainty of ±25 nm. [Brief explanation of the drawings]

[0029] For a fuller understanding of the nature and objects of the present disclosure, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] 1 is a flowchart of a method according to the present disclosure. [Figure 2] FIG. 1 is a block diagram of a system according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0030] Although the claimed subject matter is described in terms of certain embodiments, other embodiments, including embodiments that do not provide all of the benefits and features described herein, are also within the scope of this disclosure. Various structural, logical, process step, and electronic changes may be made without departing from the scope of this disclosure. Accordingly, the scope of this disclosure is defined solely by reference to the appended claims.

[0031] Using the embodiments disclosed herein, the SEM image is aligned to the design at a location near the target, and then the stage is moved to the target location for defect detection. The pixel-to-design alignment (PDA) target can be reused to obtain anchor positions for all array targets. If the anchor sites are 1-2 mm away from the target sites, a stage inaccuracy of ±125 nm can be reduced to approximately ±25 nm.

[0032] 1 is a flowchart of a method 100. At 101, an SEM tool receives a results file for a wafer from an optical inspection system, such as a BBP inspection system. The results file includes anchor points on the wafer. In one example, the results file is a KLARF file used by KLA Corporation and may include defect locations, features extracted from images acquired at those locations, image patches, defect classifications, or other information.

[0033] Anchor locations can be added to the results file for each defect location (array). These defect locations can be added as new defect locations, but the defect locations can have their own coarse bin code to identify them as anchor points. Although disclosed with respect to arrays, anchor locations can be used in random designs where there is sparse geometry around the defect location such that alignment does not work at the defect site.

[0034] The anchor points can be determined using an optical inspection system. For example, the optical inspection system can generate pixel-to-design alignment image patches. The optical inspection system can perform the pixel-to-design alignment and save the image patches and design clips.

[0035] The anchor point is selected from the pixel-to-design alignment image patches. In one example, the anchor point is selected from the pixel-to-design alignment image patches using a GAN. Determining the anchor point may include ranking the pixel-to-design alignment image patches and selecting one of the pixel-to-design alignment image patches as the anchor point. The GAN can be trained on a sampling of representative patterns using the design clip and corresponding optical and SEM images. The ranking can be based on alignment quality and uniqueness metrics of the image patches. The image patch with better alignment quality and uniqueness can be selected.

[0036] Thus, the optical inspection system can render the design clip at every pixel-to-design alignment or sub-selected location. The optical inspection system can determine whether the location is suitable for SEM alignment, which can be similar to a ranking based on image quality and uniqueness metrics. If a trained GAN network for this layer is available, an SEM-like image can be generated for further analysis of alignment suitability. The SEM-like image can be generated using a GAN with the design file as input.

[0037] In one example, an optical inspection system can perform a process, which may be an offline process, that renders one or more design clips as black and white images at an SEM image scale (e.g., 2 nm pixel size). The optical inspection system can determine whether the location is a suitable alignment target. Aspects of the rendered image, such as pattern repetition, image contrast, noise, or other aspects, can be considered to determine whether the location is acceptable for SEM alignment. A compatibility matrix for each target can be generated. Graphical Design System (GDS) locations of selected targets can be saved as part of a recipe for the optical inspection tool. GDS is a format that can be used to store semiconductor device designs.

[0038] In one example, one target is selected per 1 μm x 1 μm grid. For a 30 mm x 30 mm die, this results in 900 GDS locations. GAN or design rendering can be used to perform sub-selection of GDS locations. Pixel-to-design alignment locations can be stored. During runtime, the pixel-to-design alignment location closest to each defect can be added to that location and a review image can be captured.

[0039] The optical inspection system can also add anchor points to the result file.

[0040] The optical inspection system can adjust the target position in the target image frame given the alignment correction found at the anchor point. There may be a shift in the X direction and the vertical Y direction based on the alignment correction.

[0041] The optical inspection system can also apply positional filters to reduce nuisance. Design-defined regions of concern can be applied using precise defect coordinates. Positional filters can be care areas that can be defined in the GDS to avoid certain structures.

[0042] At 102, a defect review image is generated at an anchor point on the wafer using an SEM.

[0043] At 103, the design clip is aligned to the defect review image at the anchor point using a GAN, thereby generating an aligned defect review image. For example, the design clip may be a 1 mm x 1 mm area on a die on a wafer, or the size of the review image. Of course, the design clip may be other sizes. Fine alignment of the defect review image can be performed using targets on the defect review image. Coarse alignment can be performed on the anchor location image, which may not be within the repeat area. Fine alignment can be performed on the defect location image, which may not be aligned to adjacent cells. For example, the design clip is used as input to generate an SEM-like image used for alignment.

[0044] In one example, a stage holding the wafer can be moved to a target position for defect detection.

[0045] The aligned defect review image can have a position uncertainty of ±25 nm, which is the expected accuracy given residual errors in alignment. Accurate defect localization can be important for obtaining accurate defect classification based on high-resolution SEM images, ensuring that the correct pixels from the SEM image are used in the classification. Different position uncertainties can be provided, which can be used in certain applications. A position uncertainty of ±25 nm provides an improvement over conventional systems.

[0046] At 104, defects are detected in the aligned defect review image. This can be a coordinate correction of the defect location found in the review image. An accurate overlay of the defects found in the SEM review and BBP optical images can be provided. The resolution of the SEM tool can be used to classify the defects. For example, defect detection can occur during array mode defect detection. A coarse design-to-SEM alignment can be performed at the nearest anchor point. Fine alignment can be performed at the target location. This can be useful when there are two defects in a single field of view, as a lack of alignment can result in the wrong defect being classified or a search being performed in the wrong location.

[0047] SEM images of all result file positions can be collected on the optical inspection system workstation.

[0048] The integration of an optical inspection tool with an SEM tool can allow for the design position to be obtained from the optical inspection tool during the pixel-to-design alignment setup step, which provides a throughput advantage over what the SEM tool can do alone.

[0049] The result file can add an anchor point for each defect. One anchor point can be added for several defects if the defects are within a certain radius. The radius can be a function of the cell size and the accuracy of the SEM review tool. The accuracy of the SEM review tool can also be a function of the distance between the anchor point and the target location. If there are clusters of defects, the radius can be optimized.

[0050] For each defect corresponding to the anchor SEM image where it is located, a design clip can be extracted. The design clip can be rendered (using an image or GAN), and the rendered clip can be aligned to the corresponding SEM image. The determined offset can be used to correct the defect location of the corresponding target defect. This reduces the position uncertainty from the traditional ±125 nm to ±25 nm.

[0051] In one example, the die can be divided into a 1 mm x 1 mm grid (or some other predetermined grid unit), and one or more locations per grid can be selected as anchor points. The grids can be ranked; thus, a predictable number of anchor locations are available, satisfying the maximum allowable distance from the target to the anchor location. The location filter used during defect detection can be adjusted to be smaller after such anchor alignment is successful.

[0052] 2 is a block diagram of an embodiment of a system 200. The system 200 includes a wafer inspection tool (including an electron column 201) configured to generate an image of a wafer 204.

[0053] The wafer inspection tool includes an output acquisition subsystem including at least an energy source and a detector. The output acquisition subsystem may be an electron beam-based output acquisition subsystem. For example, in one embodiment, the energy directed at the wafer 204 includes electrons, and the energy detected from the wafer 204 includes electrons. In this manner, the energy source may be an electron beam source. In one such embodiment shown in FIG. 2, the output acquisition subsystem includes an electron column 201 coupled to a computer subsystem 202. A stage 210 may hold the wafer 204.

[0054] 2, electron column 201 includes an electron beam source 203 configured to generate electrons that are focused onto wafer 204 by one or more elements 205. Electron beam source 203 may include, for example, a cathode source or an emitter tip. One or more elements 205 may include, for example, a gun lens, an anode, a beam-limiting aperture, a gate valve, a beam current-selecting aperture, an objective lens, and a scanning subsystem, all of which may include any such suitable elements known in the art.

[0055] Electrons returning from wafer 204 (e.g., secondary electrons) may be focused onto detector 207 by one or more elements 206. One or more elements 206 may include a scanning subsystem, which may be, for example, the same scanning subsystem included in element 205.

[0056] Electron column 201 may also include any other suitable elements known in the art.

[0057] 2, the electron column 201 is shown as being configured so that electrons are directed at the wafer 204 at an oblique angle of incidence and scattered from the wafer 204 at another oblique angle, the electron beam may be directed at the wafer 204 at any suitable angle and scattered therefrom. Furthermore, the electron beam-based output acquisition subsystem may be configured to use multiple modes to generate images of the wafer 204 (e.g., having different illumination angles, collection angles, etc.). The multiple modes of the electron beam-based output acquisition subsystem may differ in any image-generating parameter of the output acquisition subsystem.

[0058] The computer subsystem 202 may be coupled to the detector 207 as described above. The detector 207 may detect electrons returning from the surface of the wafer 204, thereby forming an electron beam image of the wafer 204. The electron beam image may include any suitable electron beam image. The computer subsystem 202 may be configured to perform any of the functions described herein using the output of the detector 207 and / or the electron beam image. The computer subsystem 202 may be configured to perform any additional steps described herein. The system 200 including the output acquisition subsystem shown in FIG. 2 may be further configured as described herein.

[0059] It should be noted that FIG. 2 is provided herein to schematically illustrate an electron beam-based power acquisition subsystem configuration that may be used in the embodiments described herein. The electron beam-based power acquisition subsystem configuration described herein may be modified to optimize the performance of the power acquisition subsystem, as is typically done when designing commercial power acquisition systems. In addition, the systems described herein may be implemented using existing systems (e.g., by adding the functionality described herein to the existing system). For some such systems, the methods described herein may be provided as optional functionality of the system (e.g., in addition to other functions of the system). Alternatively, the systems described herein may be designed as entirely new systems.

[0060] Although the output acquisition subsystem is described above as an electron beam-based output acquisition subsystem, the output acquisition subsystem may also be an ion beam-based output acquisition subsystem. Such an output acquisition subsystem may be configured as shown in FIG. 2, except that the electron beam source may be replaced with any suitable ion beam source known in the art. In addition, the output acquisition subsystem may be any other suitable ion beam-based output acquisition subsystem, such as those included in commercially available focused ion beam (FIB) systems, helium ion microscope (HIM) systems, and secondary ion mass spectrometry (SIMS) systems.

[0061] The computer subsystem 202 includes a processor 208 and an electronic data storage unit 209. The processor 208 may include a microprocessor, microcontroller, or other device.

[0062] Computer subsystem 202 may be coupled to the components of system 200 in any suitable manner (e.g., via one or more transmission media, which may include wired and / or wireless transmission media) such that processor 208 can receive the output. Processor 208 may be configured to perform several functions using the output. A wafer inspection tool may receive instructions or other information from processor 208. Processor 208 and / or electronic data storage unit 209 may optionally be in electronic communication with another wafer inspection tool, wafer metrology tool, or wafer review tool (not shown) to receive additional information or send instructions.

[0063] The processor 208 is in electronic communication with a wafer inspection tool, such as the detector 207. The processor 208 may be configured to process images generated using measurements from the detector 207. For example, the processor may perform an embodiment of the method 100.

[0064] Computer subsystem 202, other systems, or other subsystems described herein may be part of a variety of systems, including a personal computer system, an image computer, a mainframe computer system, a workstation, a network appliance, an Internet appliance, or other devices. A subsystem or system may include any suitable processor known in the art, such as a parallel processor. Additionally, a subsystem or system may include a platform with high-speed processing and software, either as a standalone tool or a network tool.

[0065] The processor 208 and electronic data storage unit 209 may be located within or part of the system 200 or another device. In one example, the processor 208 and electronic data storage unit 209 may be part of a stand-alone control unit or may be a centralized quality control unit. Multiple processors 208 or electronic data storage units 209 may be used.

[0066] The processor 208 may actually be implemented by any combination of hardware, software, and firmware. Also, its functions as described herein may be performed by one unit or divided among different components, each of which may in turn be implemented by any combination of hardware, software, and firmware. Program codes or instructions for the processor 208 to implement the various methods and functions may be stored in a readable storage medium, such as memory in the electronic data storage unit 209 or other memory.

[0067] Where system 200 includes multiple computer subsystems 202, the different subsystems may be coupled to one another such that images, data, information, instructions, etc., can be transmitted between the subsystems. For example, one subsystem may be coupled to additional subsystems by any suitable transmission medium, which may include any suitable wired and / or wireless transmission medium known in the art. Two or more of such subsystems may also be effectively coupled by a shared computer-readable storage medium (not shown).

[0068] The processor 208 may be configured to perform a number of functions using the output of the system 200 or other outputs. For example, the processor 208 may be configured to send the output to an electronic data storage unit 209 or another storage medium. The processor 208 may be further configured as described herein.

[0069] In one example, processor 208 is configured to receive wafer results from an optical inspection system, such as optical inspection system 211. The result file includes an anchor point on the wafer. Processor 208 generates a defect review image at the anchor point on wafer 204; aligns a design clip to the defect review image at the anchor point, thereby generating an aligned defect review image; and detects defects in the aligned defect review image. The design clip may be a 1 mm x 1 mm area on a die on wafer 204. The aligned defect review image may have a position uncertainty of ±25 nm. The 1 mm x 1 mm area may be used based on the accuracy of the SEM review tool and the capabilities of the image context around the defect so that image processing algorithms can align and perform defect detection and classification. Smaller design clip sizes are possible; 1 mm x 1 mm is merely an example.

[0070] In this example, optical inspection system 211 can be configured to pixel-to-design alignment image patches. Anchor points are selected from the pixel-to-design alignment image patches. A GAN unit within computer subsystem 202 or optical inspection system 211 can be configured to select anchor points from the pixel-to-design alignment image patches. The GAN unit can be a processor, such as processor 208, or can be executed by a processor.

[0071] Processor 208 may be further configured to perform fine alignment of the defect review image using targets on the defect review image.

[0072] The processor 208 can also be configured to align the SEM image to the design at a location near the target. The processor 208 can send instructions to the stage 208 to move to the target location for defect detection.

[0073] Processor 208 or computer subsystem 202 may be part of a defect review system, an inspection system, a metrology system, or some other type of system. Accordingly, the embodiments disclosed herein describe several configurations that can be tailored in several ways for systems with different capabilities that are more or less suitable for different applications.

[0074] Processor 208 may be configured according to any of the embodiments described herein. Processor 208 may also be configured to perform other functions or additional steps using the output of system 200 or using images or data from other sources.

[0075] Processor 208 may be communicatively coupled to any of the various components or subsystems of system 200 in any manner known in the art. For example, computer subsystem 202 may be coupled to optical inspection system 211. Additionally, processor 208 may be configured to receive and / or acquire data or information from other systems (e.g., inspection results from an inspection system such as a review tool, a remote database containing design data, etc.) via a transmission medium, which may include wired and / or wireless portions. In this manner, the transmission medium may serve as a data link between processor 208 and other subsystems of system 200 or systems external to system 200.

[0076] The various steps, functions, and / or operations of system 200 and the methods disclosed herein may be performed by one or more of the following: electronic circuits, logic gates, multiplexers, programmable logic devices, ASICs, analog or digital controls / switches, microcontrollers, or computing systems. Program instructions implementing methods such as those described herein may be transmitted over or stored on a carrier medium. The carrier medium may include a storage medium such as a read-only memory, a random-access memory, a magnetic or optical disk, a non-volatile memory, a solid-state memory, or a magnetic tape. The carrier medium may include a transmission medium such as a wire, a cable, or a wireless transmission link. For example, the various steps described throughout this disclosure may be performed by a single processor 208 (or computer subsystem 202) or, alternatively, by multiple processors 208 (or multiple computer subsystems 202). Furthermore, different subsystems of system 200 may include one or more computing or logic systems. Therefore, the above description should not be construed as a limitation on the present disclosure, but merely as illustrative.

[0077] In one example, a non-transitory computer-readable storage medium containing one or more programs is provided. The one or more programs are configured to execute the following steps on one or more processors: first, receive results for a wafer from an optical inspection system; the result file includes anchor points on the wafer; second, generate a defect review image at the anchor points on the wafer; third, align a design clip to the defect review image at the anchor points, thereby generating an aligned defect review image; and fourth, detect defects in the aligned defect review image. The aligned defect review image can have a position uncertainty of ±25 nm.

[0078] The optical inspection system can be configured to generate pixel-to-design alignment image patches, and the anchor points can be selected from the pixel-to-design alignment image patches. In one example, the anchor points are selected from the pixel-to-design alignment image patches using a GAN.

[0079] The anchor points can be received by the SEM from the optical inspection system via a results file.

[0080] The one or more programs may be further configured to perform precision alignment of the defect review image using targets on the defect review image.

[0081] The method steps described in the various embodiments and examples disclosed herein are sufficient to practice the methods of the present invention. Thus, in some embodiments, the method consists essentially of a combination of the method steps disclosed herein. In other embodiments, the method consists of such steps.

[0082] Each of the steps of the method may be performed as described herein. The method may also include any other steps that may be performed by a processor and / or computer subsystem or system described herein. The steps may be performed by one or more computer systems that may be configured according to any of the embodiments described herein. In addition, the above-described method may be implemented by any of the system embodiments described herein.

[0083] Although the present disclosure has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present disclosure may be made without departing from the scope of the present disclosure.

Claims

1. 1. A method comprising: determining anchor points on the wafer using pixel-to-design alignment image patches generated by the optical inspection system; receiving, at a scanning electron microscope tool, a results file for a wafer from an optical inspection system, the results file including anchor points on the wafer, defect locations on the wafer, and defect classifications at the defect locations; generating a defect review image at the anchor point on the wafer using a scanning electron microscope; aligning a design clip to the defect review image at the anchor point, thereby generating an aligned defect review image, the design clip including an area on the wafer; and detecting defects in the aligned defect review image; A method for providing the above.

2. The method of claim 1, further comprising selecting the anchor point from the pixel-to-design alignment image patch.

3. The method of claim 2 , wherein the anchor points are selected from the pixel-to-design alignment image patches using a generative adversarial network.

4. 3. The method of claim 2, wherein determining the anchor point comprises ranking the pixel-to-design alignment image patches and selecting one of the pixel-to-design alignment image patches as the anchor point.

5. 10. The method of claim 1, wherein the design clip is a 1 mm x 1 mm area on a die on a wafer.

6. The method of claim 1 , further comprising: performing precision alignment of the defect review image using a target on the defect review image.

7. 10. The method of claim 1, wherein the aligned defect review image has a position uncertainty of ±25 nm.

8. The method of claim 1 , wherein the detection is performed in an array mode.

9. 1. A system comprising:

1. A scanning electron microscope tool comprising: a stage configured to hold a wafer; an electron beam source configured to emit electrons toward the wafer; a detector configured to detect electrons received from the wafer; a processor in electronic communication with the scanning electron microscope, receiving a results file for the wafer from the optical inspection system, the results file including anchor points on the wafer, defect locations on the wafer, and defect classifications at the defect locations; generating a defect review image at the anchor point on the wafer; aligning a design clip to the defect review image at the anchor point, thereby generating an aligned defect review image, the design clip including an area on the wafer; a processor configured to detect defects in the aligned defect review image; A system comprising:

10. 10. The system of claim 9, further comprising an optical inspection system configured to generate a pixel-to-design alignment image patch, and wherein the anchor point is selected from the pixel-to-design alignment image patch.

11. The system of claim 10 , further comprising a generative adversarial network unit configured to select the anchor points from pixel-to-design alignment image patches.

12. 10. The system of claim 9, wherein the design clip is a 1 mm x 1 mm area on a die on the wafer.

13. 10. The system of claim 9, wherein the processor is further configured to perform fine alignment of the defect review image using targets on the defect review image.

14. 10. The system of claim 9, wherein the aligned defect review image has a position uncertainty of ±25 nm.

15. On one or more processors, receiving a results file for the wafer from an optical inspection system, the results file including anchor points on the wafer, defect locations on the wafer, and defect classifications at the defect locations; generating a defect review image at an anchor point on the wafer; aligning a design clip to the defect review image at the anchor point, thereby generating an aligned defect review image, the design clip including an area on the wafer; and detecting defects in the aligned defect review image; 1. A non-transitory computer-readable storage medium containing one or more programs configured to execute:

16. 16. The computer-readable storage medium of claim 15, wherein the optical inspection system is configured to generate pixel-to-design alignment image patches, and the anchor points are selected from the pixel-to-design alignment image patches.

17. 17. The computer-readable storage medium of claim 16, wherein the anchor points are selected from the pixel-to-design alignment image patches using a generative adversarial network.

18. 16. The computer-readable storage medium of claim 15, wherein the one or more programs are further configured to perform precision alignment of the defect review image using targets on the defect review image.

19. 16. The computer-readable storage medium of claim 15, wherein the aligned defect review image has a position uncertainty of ±25 nm.

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