Determine the location of the suspected defect

Abstract

Method, non-transitory computer-readable medium, and detection system for determining the location of a suspected defect on a substrate.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of US 16 / 808,111, filed on March 3, 2020. The disclosure of the said application is incorporated herein by reference in its entirety and for all purposes. Background Art

[0003] Wafers, such as semiconductor wafers, undergo multiple mechanical and chemical processes that can cause various types of defects.

[0004] Wafer inspection and examination are performed in two stages. During the first stage, an optical wafer inspection system discovers suspicious defects and generates location information regarding the locations of the suspicious defects.

[0005] During the second stage, a charged - particle inspection system (such as a scanning electron microscope) examines the suspicious defects and determines which of the suspicious defects are actual defects.

[0006] The optical wafer inspection system is much faster than the charged - particle inspection system and can scan the entire wafer in a relatively short period of time. The resolution of the charged - particle inspection system is much finer than that of the optical wafer inspection system and can inspect nanoscale defects. Thus, two - stage wafer inspection and examination provide a trade - off between speed and accuracy.

[0007] The optical wafer inspection system and the charged - particle inspection system are different from each other, and the wafers inspected by the optical wafer inspection system are mechanically moved to the charged - particle inspection system.

[0008] For various reasons, the charged - particle inspection system cannot assume that the suspicious defects are exactly located at the positions indicated in the location information of the suspicious defects measured by the optical wafer inspection system. The various reasons can include inaccuracies in the position measurement of the charged - particle inspection system, inaccuracies in the navigation of the charged - particle inspection system, and misalignment between the charged - particle inspection system and the optical wafer inspection system.

[0009] Therefore, the charged - particle inspection system must search for the suspicious defects within a relatively large search window centered on the location of the suspicious defects.

[0010] The search process is time - consuming.

[0011] There is an increasing need to provide a more accurate search process. Summary of the Invention

[0012] A method, a non - transitory computer - readable medium, and a system for determining the location of a suspicious defect can be provided. Brief Description of the Drawings

[0013] In the concluding part of the specification, the subject matter regarded as embodiments of the present disclosure is particularly pointed out and protection is explicitly claimed. However, the embodiments of the present disclosure regarding the organization and method of operation, as well as their objectives, features, and advantages, can be best understood by referring to the following detailed description when read in conjunction with the accompanying drawings, in which:

[0014] Figure 1 Examples of the method are shown;

[0015] Figure 2 An example of dividing a wafer into five regions is shown;

[0016] Figure 3 An example of a linear estimator selected by calculating the least square error is shown;

[0017] Figure 4 Examples of the distribution, histogram, and matching filtering function of multiple CPRS determination positions estimated are shown;

[0018] Figure 5 Examples of the method are shown; and

[0019] Figure 6 Examples of the system are shown. Detailed Description of the Embodiments

[0020] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure.

[0021] However, those skilled in the art will understand that the current embodiments of the present disclosure can be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the current embodiments of the present disclosure.

[0022] In the concluding part of the specification, the subject matter regarded as embodiments of the present disclosure is particularly pointed out and protection is explicitly claimed. However, the embodiments of the present disclosure regarding the organization and method of operation, as well as their objectives, features, and advantages, can be best understood by referring to the following detailed description when read in conjunction with the accompanying drawings.

[0023] It should be understood that, for simplicity and clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Additionally, where considered appropriate, reference numerals may be repeated between the drawings to indicate corresponding or similar elements.

[0024] Since the illustrated embodiments of the present disclosure can be implemented mostly using electronic components and circuits known to those skilled in the art, in order to understand and appreciate the basic concepts of the current embodiments of the present disclosure and in order not to obscure or distract from the teachings of the current embodiments of the present disclosure, the details will not be explained to a greater extent than considered necessary above.

[0025] Any reference in the specification to a method should be applied, with necessary modifications in details, to a system capable of performing the method and should be applied, with necessary modifications in details, to a non - transitory computer - readable medium storing instructions for performing the method.

[0026] Any reference in the specification to a system should be applied, with necessary modifications in details, to a method executable by the system and should be applied, with necessary modifications in details, to a non - transitory computer - readable medium storing instructions executable by the system.

[0027] Any reference in the specification to a non - transitory computer - readable medium should be applied, with necessary modifications in details, to a method applicable when executing instructions stored in the computer - readable medium and should be applied, with necessary modifications in details, to a system configured to execute instructions stored in the computer - readable medium.

[0028] The term “and / or” means additionally or alternatively.

[0029] The terms “comprising”, “having”, “consisting of” and “consisting essentially of” are used interchangeably. Any reference to one of these terms can be applied, with necessary modifications in details, to any other of these terms.

[0030] The term “configured” can mean “constructed and arranged” and / or programmed.

[0031] The following terms are used in the specification:

[0032] ο Optical Wafer Inspection System (OWIS): A wafer inspection system that uses light to detect defects. The OWIS can irradiate wafers with visible light radiation, ultraviolet radiation, deep ultraviolet radiation, and extreme ultraviolet radiation. Non - limiting examples of OWIS include the UVision TM series manufactured by Applied Materials, Inc. in California, USA.

[0033] ο OWIS - determined location of a suspected defect: The location (e.g., coordinates) of a suspected defect measured by the OWIS.

[0034] ο Charged Particle Review System (CPRS): A charged particle inspection system that uses charged particle radiation to inspect for defects. The CPRS can irradiate a suspected defect and its vicinity with an electron beam or an ion beam. Non-limiting examples of the CPRS include the SEM-Vision series manufactured by Applied Materials, Inc., in California, USA. TM Series.

[0035] ο CPRS-determined location of a suspected defect: The location (e.g., coordinates) of a suspected defect measured by the CPRS.

[0036] ο Alignment-related mapping: A mapping between (a) the OWIS-determined locations of suspected defects belonging to a subgroup of suspected defects forming an alignment and (b) the CPRS-determined locations of the suspected defects belonging to the subgroup.

[0037] Figure 1 An example of method 100 is shown.

[0038] Method 100 may start with step 110, which is to receive the OWIS-determined locations of suspected defects on a wafer. The OWIS-determined locations of suspected defects on the wafer may be received by the CPRS.

[0039] The OWIS-determined locations of suspected defects on the wafer may be provided in different formats, such as through a distribution map of the suspected defects.

[0040] The suspected defects may be spread throughout the entire wafer, or only in some parts of the wafer.

[0041] After step 110 may be step 120, which is to inspect multiple suspected defects.

[0042] The multiple suspected defects may be located within one or more regions of the wafer.

[0043] Figure 2 An example of dividing wafer 10 into five regions is shown: a first region 201, a second region 202, a third region 203, a fourth region 204, and a fifth region 205. The first region 201 is a circle located at the center of wafer 10. The other regions are segments of the annular portion of the wafer surrounding the first region.

[0044] These regions may differ in shape and size from Figure 2 the regions.

[0045] Returning to reference Figure 1 , the inspection may include searching for multiple suspected defects at an initial search window. The initial search window may be defined to include the suspected defects. The initial search window may be defined based on the OWIS-determined locations of the suspected defects in the group. The initial search window may be a part of a region of the wafer.

[0046] After step 120, there may be step 130, which filters multiple suspicious defects to select suspicious defects that form a group of suspicious defects based on one or more selection criteria.

[0047] The filtering may include rejecting suspicious defects outside a certain size range, rejecting suspicious defects that reach the boundary of the initial search window and extend beyond the initial search window.

[0048] As another example, suspicious defects are filtered based on the ratio between the highest and the second highest automatic defect detection (ADR) scores.

[0049] The group of suspicious defects is only a part of the suspicious defects on the substrate.

[0050] The size of the group (the number of suspicious defects in each group) can be determined in various ways. For example, based on the success or failure of previous attempts to find suspicious defects, etc., the size can be fixed.

[0051] At the end of step 130, the group of suspicious defects and the CPRS determination positions of the group of suspicious defects are known. Table 1 shows an example of the results of step 130.

[0052] X coordinate determined by OWIS Y coordinate determined by OWIS X coordinate determined by CPRS Y coordinate determined by CPRS Xo1 Yo1 Xc1 Yc1 Xo2 Yo2 Xc2 Yc2 …… …… …… …… …… …… …… …… XoNg YoNg XcNg YcNg

[0053] Table 1

[0054] Assume that the group of suspicious defects includes a first number (Ng) of suspicious defects. Ng is a positive integer greater than 1.

[0055] Method 100 may include searching for a predefined number of filtered suspicious defects within one area of the wafer, and then searching for the next filtered suspicious defects within another area of the wafer.

[0056] After step 130, there may be step 140, which defines multiple permutations of the suspicious defects. Each permutation of the suspicious defects is formed by a subgroup of the group of suspicious defects.

[0057] Each subgroup includes a second number (Ns) of suspicious defects. Ns is less than Ng.

[0058] Step 140 may include defining all possible permutations of the suspicious defects. For example, for a given group of size Ng, all possible permutations of size Ns.

[0059] After step 140, there may be step 150, which calculates a permutation-related map for each permutation of the suspicious defects (among the multiple permutations of the suspicious defects).

[0060] The result of step 150 is multiple permutation-related maps.

[0061] Each permutation - related mapping maps (a) the CPRS - determined positions of the suspect defects of a permutation to (b) the OWIS - determined positions of the suspect defects of the permutation; wherein each permutation of the suspect defects is formed by a subgroup of the suspect - defect group.

[0062] The calculations can be implemented in various ways, such as by linear estimation.

[0063] All permutation mappings can consider one or more sources of positional error, such as X - Y offset, scaling, and rotation.

[0064] Figure 3 An example of a linear estimator selected by calculating the least - square error is shown.

[0065] The permutation - related mapping matrix 283 multiplied by the OWIS coordinate matrix 282 equals the CPRS coordinate matrix 281.

[0066] At Figure 3 In

[0067] A simpler permutation - related mapping, such as one that represents only the X - Y offset, will include a vector with only one pair of coefficients (e.g., a vector including elements A0, B0, and zeros).

[0068] Return reference Figure 1 After step 150, step 160 can follow, where step 160 is to select a selected permutation - related mapping.

[0069] Step 160 can include step 162 and step 168.

[0070] Step 162 can include calculating a score for each of the multiple permutation - related mappings to provide multiple scores.

[0071] Step 168 can include selecting a selected permutation based on the multiple scores.

[0072] Step 162 can include step 164 and step 166.

[0073] Step 164 can include applying each of the multiple permutation - related mappings to the OWIS - determined positions of the suspect - defect group to provide multiple estimated CPRS - determined positions of the suspect - defect group.

[0074] Step 166 can include calculating a score for each of the multiple permutation - related mappings based on the multiple CPRS - determined positions of the suspect - defect group.

[0075] The score can reflect the distribution of the determined positions of multiple CPRSs of the group, and a more compact distribution can obtain a higher score.

[0076] Figure 4 Examples are shown as follows: (a) the distribution 271 of the estimated determined positions of multiple CPRSs of a group of suspected defects, (b) the histogram 272 of the distances of the multiple CPRS determined positions from the center of the distribution, and (c) the matching filtering function 273 applied to the distances from the center to provide a score, which is the weighted sum of the distances from the center.

[0077] Return reference Figure 1 , step 168 may include selecting the permutation with the highest score (e.g., the highest weighted sum).

[0078] After step 160, step 170 may follow. Step 170 is to determine whether to use the selected permutation-related mapping to convert the OWIS determined positions of the suspected defects on the substrate into the CPRS determined positions of the suspected defects on the substrate.

[0079] The determination can be made in various ways, such as by determining whether the selected permutation-related mapping exhibits a sufficiently high certainty level (CL).

[0080] Step 170 may include step 172. Step 172 is to calculate the chance of a uniformly distributed random sample occurring after applying the selected permutation-related mapping within a predefined field of view (FOV) of the CPRS with a predefined width d. The predefined width (d) is less than the predefined width (L) of the initial FOV of the CPRS, and the initial FOV of the CPRS is the FOV of the CPRS used before applying method 100.

[0081] The value of the chance (n) is given as an input to method 100. The value of the probability (P) of having a suspected defect within the predefined FOV is also given as an input to method 100 and is equal to (d / L) 2 .

[0082] Step 172 may include determining the CL by calculating the following equation:

[0083]

[0084] When it is determined (in step 170) to use the selected permutation-related mapping, then step 180 may follow step 170. Step 180 is to convert the OWIS determined positions of the suspected defects on the substrate into the CPRS determined positions of the suspected defects on the substrate by using the selected permutation-related mapping.

[0085] After step 180, step 190 may follow. Step 190 is to inspect a suspected defect based on the position of the CPRS of the suspected defect on the substrate.

[0086] This may include defining an inspection search window including the position of the CPRS of the suspected defect on the substrate and inspecting the suspected defect located within the inspection search window.

[0087] When it is determined (in step 170) not to use the selected permutation-related mapping, then after step 170, step 174 may follow. Step 174 is to increase the number of suspected defects within the group, that is, increase the number of suspected defects to be included among the multiple suspected defects.

[0088] Increasing the number of suspected defects extends the execution cycle of method 100, but the level of certainty associated with the execution of method 100 can be increased by evaluating more suspected defects.

[0089] After step 174, step 130 may follow.

[0090] Multiple iterations of steps 130, 140, 150, 160, 170, and 174 may be performed. The iteration may stop when a certain level of certainty is obtained, and additionally or alternatively, the iteration may stop after reaching a predefined number of iterations.

[0091] Method 100 (particularly step 150) shows calculating a single permutation-related mapping for each permutation.

[0092] It should be noted that step 150 may include calculating different permutation-related mappings for each permutation.

[0093] The different permutation-related mappings may include the aforementioned permutation-related mapping and one or more additional permutation-related mappings.

[0094] The different permutation-related mappings for each permutation may differ from each other in terms of computational complexity. For example, there may be one or more sources of positional error, such as X-Y offset, scaling, and rotation. Different permutations may consider different numbers of sources of positional error. A simple permutation-related mapping may consider only one source of positional error, such as X-Y offset. A more complex permutation-related mapping may consider two or more sources of positional error, such as X-Y offset, scaling, and rotation.

[0095] The choice of which type (or types) of permutation-related mapping to use may be preset, may change over time, may change between one iteration and another (of steps 130, 140, 150, 160, 170, and 174), may be based on a comparison between scores associated with different types of permutation-related mappings, and so on.

[0096] For example, a simple permutation-related mapping can be used during one or more first iterations of steps 130, 140, 150, 160, 170, and 174. Assuming that one or more additional iterations need to be performed again, the level of certainty obtained during one of the first iterations can indicate that a more complex permutation-related mapping should be evaluated. If the level of certainty is not high enough, this can indicate that the simple permutation-related mapping is not accurate enough, and a more complex permutation-related mapping can be used.

[0097] Even when deciding to use a more complex permutation-related mapping, the method can apply the simple permutation-related mapping and then compare between the scores of the simple permutation-related mapping and the more complex permutation-related mapping to determine which permutation-related mapping to use in the current iteration or the next iteration.

[0098] The choice of the type of permutation-related mapping can also be based on the resources available for performing method 100 and / or based on the time allocated to complete method 100. Using a more complex permutation-related mapping may require more resources and / or more available time.

[0099] When more than a single type of permutation-related mapping is selected, method 100 can include at least one of the following:

[0100] ο For each permutation of the suspected defects among multiple permutations of the suspected defects, calculate additional permutation-related mappings to provide multiple additional permutation-related mappings. For at least one of the multiple permutations, the additional permutation-related mapping of the permutation is different from the permutation-related mapping of the permutation in terms of complexity. For at least one of the multiple permutations, the additional permutation-related mapping of the permutation is different from the permutation-related mapping of the permutation in terms of the number of sources of positional error. For example, the permutation-related mapping can only consider the X-Y offset, while the additional permutation-related mapping can consider at least one of scaling and rotation and the X-Y offset.

[0101] ο Calculate scores for each of the additional multiple permutation-related mappings to provide additional multiple scores.

[0102] ο Select a selected permutation based on the multiple scores (of the multiple permutation-related mappings) and based on the additional multiple scores.

[0103] Figure 5 Method 102 is shown.

[0104] Method 102 can start with step 110, which is to receive the OWIS determination location of the suspected defect of the wafer. The OWIS determination location of the suspected defect of the wafer can be received by the CPRS.

[0105] After step 110 can be step 120, which is to inspect multiple suspected defects.

[0106] After step 120, step 130 may follow. Step 130 filters multiple suspicious defects to select suspicious defects that form a group of suspicious defects based on one or more selection criteria.

[0107] After step 130, step 140 may follow. Step 140 defines multiple permutations of the suspicious defects. Each permutation of the suspicious defects is formed by a subgroup of the group of suspicious defects.

[0108] After step 140, step 152 may follow. Step 152 calculates different permutation-related mappings for each permutation of the suspicious defects (among the multiple permutations of the suspicious defects).

[0109] The different permutation-related mappings of the permutations can be regarded as a set of permutation-related mappings.

[0110] The result of step 152 is multiple sets of permutation relationship mappings.

[0111] After step 152, step 160 may follow. Step 160 selects selected permutation-related mappings.

[0112] The selection should be made among the multiple sets of permutation relationship mappings. Therefore, steps 162, 164, 166, and 168 can be applied to all the permutation-related mappings in the multiple sets of permutation relationship mappings.

[0113] Step 160 may further include step 169. Step 169 determines which types of permutations to use during the next iteration of steps 130, 140, 152, 160, 170, and 174.

[0114] A type of permutation-related mapping that provides a better trade-off between CL and resource consumption can be performed. As another example, as long as the simpler permutation-related mapping provides at least a predefined CL, the simpler permutation-related mapping can be selected.

[0115] After step 160, step 170 may follow. Step 170 determines whether to use the selected permutation-related mapping to convert the OWIS determined position of the suspicious defects on the substrate to the CPRS determined position of the suspicious defects on the substrate.

[0116] The determination can be made in various ways, for example, by determining whether the selected permutation-related mapping exhibits a sufficiently high level of certainty (CL).

[0117] When it is determined (in step 170) to use the selected permutation-related mapping, then after step 170, step 180 may follow. Step 180 converts the OWIS determined position of the suspicious defects on the substrate to the CPRS determined position of the suspicious defects on the substrate by using the selected permutation-related mapping.

[0118] After step 180, step 190 may follow. Step 190 is to inspect a suspected defect based on the position determined by the Charged Particle Review System (CPRS) of the suspected defect on the substrate.

[0119] When it is determined (in step 170) not to use the selected arrangement-related mapping, then step 174 may follow step 170. Step 174 is to increase the number of suspected defects within the group, that is, increase the number of suspected defects to be included in the multiple suspected defects.

[0120] The increase in the number of suspected defects extends the execution cycle of method 100, but the level of certainty associated with the execution of method 100 can be increased by evaluating more suspected defects.

[0121] Step 130 may follow step 174.

[0122] Figure 6 This is an example of the charged particle review system (CPRS) 200 and the wafer 10.

[0123] The CPRS 200 includes an imager 210, a processor 220, and a memory unit 230.

[0124] The processor 220 may include one or more processing circuits, such as a microprocessor, a pre-processor (such as an image pre-processor), a graphics processor, a central processing unit (CPU), support circuits, a digital signal processor, an integrated circuit, a memory, or any other type of device suitable for running application programs and for performing any of the above methods.

[0125] The imager 210 can be an electron beam imager, an electron beam microscope, an ion microscope, an ion imager, etc. The electron beam microscope can be a scanning electron microscope, a transmission electron microscope, etc.

[0126] The system 200 can be configured to execute method 102, and additionally or alternatively, can be configured to execute method 100.

[0127] For example, the imager 210 can be configured to irradiate the suspected defect with a charged particle beam.

[0128] The processor 220 and / or the memory unit 230 can be configured to execute other steps of method 100 and / or method 102.

[0129] For example, the memory unit 230 can be configured to store the positions determined by the Optical Wafer Inspection System (OWIS) of the group of suspected defects.

[0130] For example, the processor 220 can be configured to:

[0131] ο Determine the CPRS determination location of the group of suspected defects; wherein the determination is at least partially based on the OWIS determination location of the group of suspected defects; wherein the suspected defects of the group are only a part of the suspected defects of the substrate.

[0132] ο For each permutation of the suspected defects among the multiple permutations of the suspected defects, calculate a permutation-related mapping to provide a plurality of permutation relationship mappings; wherein each permutation relationship mapping maps the CPRS determination location of the permutation of the suspected defects to the OWIS determination location of the permutation of the suspected defects; wherein each permutation of the suspected defects is formed by a subgroup of the group of suspected defects.

[0133] ο Select a selected permutation-related mapping.

[0134] ο Determine whether to use the selected permutation-related mapping to convert the OWIS determination location of the suspected defects of the substrate to the CPRS determination location of the suspected defects of the substrate.

[0135] ο When it is determined to use the selected permutation-related mapping, convert the OWIS determination location of the suspected defects of the substrate to the CPRS determination location of the suspected defects of the substrate by using the selected permutation-related mapping.

[0136] In the foregoing specification, embodiments of the present disclosure have been described with reference to specific examples of embodiments of the present disclosure. However, it will be apparent that various modifications and variations can be made therein without departing from the broader spirit and scope of the embodiments of the present disclosure as set forth in the appended claims.

[0137] In addition, the terms "front", "rear", "top", "bottom", "above", "below", etc. (if any) in the specification and claims are used for descriptive purposes only and are not necessarily used to describe a permanent relative position. It should be understood that such terms are interchangeable under appropriate circumstances so that the embodiments of the present disclosure described herein can, for example, operate in other orientations different from those illustrated or otherwise described herein.

[0138] The connections discussed herein can be of any type suitable for transmitting signals to or from various nodes, units, or devices, for example, via an intermediate device. Thus, unless otherwise implied or stated, the connections can be, for example, direct connections or indirect connections. These connections can be described or characterized with reference to a single connection, multiple connections, unidirectional connections, or bidirectional connections. However, different embodiments can vary the implementation of the connections. For example, separate unidirectional connections can be used instead of bidirectional connections, and vice versa. Similarly, multiple connections can be replaced by a single connection that transmits multiple signals in a serial manner or in a time-division multiplexed manner. Also, a single connection carrying multiple signals can be separated into various different connections carrying subsets of those signals. Thus, there are many options for transmitting signals.

[0139] Any arrangement that effectively "associates" components that perform the same function such that the desired function is achieved. Thus, any two components combined herein to perform a particular function can be considered to be "associated" with each other such that the desired function is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired function.

[0140] Furthermore, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations can be combined into a single operation, a single operation can be distributed over additional operations, and the operations can be performed at least partially overlapping in time. Additionally, alternative embodiments can include multiple instances of a particular operation, and the order of operations can be varied in various other embodiments.

[0141] Similarly, for example, in one embodiment, the illustrated examples can be implemented as circuitry located on a single integrated circuit or within the same device. Alternatively, the examples can be implemented as any number of separate integrated circuits or separate devices interconnected in a suitable manner.

[0142] However, other modifications, variations, and alternatives are also possible. Thus, the specification and drawings are to be regarded as illustrative rather than restrictive.

[0143] In a claim, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or steps than those listed in a claim. Further, the term "a" or "an" as used herein is defined as one or more than one. Also, the introductory phrases such as "at least one" and "one or more" used in the claims shall not be construed to imply that another claim element introduced by the indefinite article "a" or "an" limits any particular claim containing such introduced claim element to embodiments of the disclosure having only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" as well as the indefinite article "a" or "an". The same holds for the use of the definite article. Terms such as "first" and "second" are used herein for purposes of distinction only and are not necessarily intended to denote any temporal or other prioritization of such elements. Thus, these terms are not necessarily intended to indicate a time or other order of precedence of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

[0144] Although certain features of embodiments of the present disclosure have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. Accordingly, it is to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the embodiments of the present disclosure.

Claims

1. A method for determining the location of a suspected defect on a substrate, the method comprising: Determining, by a charged particle inspection system CPRS, a CPRS determined location of a group of suspected defects; wherein the determination is at least partially based on an optically wafer inspection system OWIS determined location of the group of suspected defects; wherein the group of suspected defects is only a part of the suspected defects of the substrate; Calculating, for each permutation of the suspected defects among a plurality of permutations of the suspected defects, a permutation correlation map to provide a plurality of permutation relationship maps; Wherein each permutation relationship map maps the CPRS determined location of the suspected defects of the permutation to the OWIS determined location of the suspected defects of the permutation; Wherein Each permutation of the suspected defects is formed by a subgroup of the group of suspected defects; Selecting a selected permutation correlation map; Determining whether to use the selected permutation correlation map to convert the OWIS determined location of the suspected defects of the substrate to the CPRS determined location of the suspected defects of the substrate; and When it is determined to use the selected permutation correlation map, converting, by using the selected permutation correlation map, the OWIS determined location of the suspected defects of the substrate to the CPRS determined location of the suspected defects of the substrate.

2. The method according to claim 1, comprising: When it is determined not to use the selected permutation correlation map, increasing the number of suspected defects within the group, followed by the steps of: Determining, by CPRS, the CPRS determined location of the group of suspected defects.

3. The method according to claim 1, comprising: Determining a certainty level of the selected permutation correlation map; and wherein the determination of whether to use the selected permutation correlation map is based on the certainty level of the selected permutation correlation map.

4. The method according to claim 1, comprising: Calculating a score for each of the plurality of permutation correlation maps to provide a plurality of scores; And selecting the selected permutation based on the plurality of scores.

5. The method according to claim 4, comprising: Applying each of the plurality of permutation correlation maps to the OWIS determined location of the group of suspected defects to provide a plurality of estimated CPRS determined locations of the group of suspected defects; and wherein the calculation of the score for each of the plurality of permutation correlation maps is based on the plurality of CPRS determined locations of the group of suspected defects.

6. The method according to claim 1, comprising: Calculating, for each permutation of the suspected defects among the plurality of permutations of the suspected defects, an additional permutation correlation map to provide a plurality of additional permutation correlation maps.

7. The method according to claim 6, wherein for at least one permutation among the plurality of permutations, the additional permutation correlation map of the permutation is different from the permutation correlation map of the permutation in terms of complexity.

8. The method according to claim 6, wherein for at least one permutation among the plurality of permutations, the additional permutation correlation map of the permutation is different from the permutation correlation map of the permutation in terms of the number of location error sources.

9. The method according to claim 6, comprising: Calculating a score for each of the plurality of permutation correlation maps to provide a plurality of scores; Calculating a score for each of the additional plurality of permutation correlation maps to provide an additional plurality of scores; And selecting the selected permutation based on the plurality of scores and based on the additional plurality of scores.

10. The method according to claim 1, comprising: Inspecting a plurality of suspected defects; Select the plurality of suspected defects based on one or more selection criteria to provide the group of suspected defects.

11. The method according to claim 10, comprising: Search for the plurality of suspected defects in different regions of the substrate.

12. A charged particle inspection system CPRS, comprising: A memory unit configured to store the optical wafer inspection system OWIS determined positions of a group of suspected defects; A processor configured to: Determine the CPRS determined positions of the group of suspected defects; wherein the determination is at least partially based on the OWIS determined positions of the group of suspected defects; wherein the group of suspected defects is only a part of the suspected defects of the substrate; For each permutation of the suspected defects in a plurality of permutations of the suspected defects, calculate a permutation correlation map to provide a plurality of permutation relationship maps; Wherein each permutation relationship map maps the CPRS determined positions of the suspected defects of the permutation to the OWIS determined positions of the suspected defects of the permutation; wherein each permutation of the suspected defects is formed by a subgroup of the group of suspected defects; Select a selected permutation correlation map; Determine whether to use the selected permutation correlation map to convert the OWIS determined positions of the suspected defects of the substrate to the CPRS determined positions of the suspected defects of the substrate; and When it is determined to use the selected permutation correlation map, convert the OWIS determined positions of the suspected defects of the substrate to the CPRS determined positions of the suspected defects of the substrate by using the selected permutation correlation map.

13. A non-transitory computer-readable medium storing instructions for: determining, by a charged particle inspection system CPRS, the CPRS determined positions of a group of suspected defects; wherein the determination is at least partially based on the optical wafer inspection system OWIS determined positions of the group of suspected defects; wherein the group of suspected defects is only a part of the suspected defects of the substrate; For each permutation of the suspected defects among the multiple permutations of the suspected defects, calculate a permutation-related mapping to provide multiple permutation relationship mappings; Wherein each permutation relationship map maps the CPRS determined positions of the suspected defects of the permutation to the OWIS determined positions of the suspected defects of the permutation; Wherein Each permutation of the suspected defects is formed by a subgroup of the group of suspected defects; Select a selected permutation correlation map; Determine whether to use the selected permutation correlation map to convert the OWIS determined positions of the suspected defects of the substrate to the CPRS determined positions of the suspected defects of the substrate; and When it is determined to use the selected permutation correlation map, convert the OWIS determined positions of the suspected defects of the substrate to the CPRS determined positions of the suspected defects of the substrate by using the selected permutation correlation map.

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