JP6041865B2 - Method and system for hybrid reticle inspection - Google Patents

Description

"priority"
No. 61 / 478,998 filed Apr. 26, 2011 and U.S. provisional application filed Mar. 15, 2012, both of which are incorporated herein by reference. No. 61 / 611,236, 35U. S. C. Claims the benefit under §119 (e).

“Field of Invention”
The present invention is generally directed to semiconductor processing, and more specifically to inspection in a hybrid inspection process.

  Inspection and measurement techniques are conventionally used in semiconductor wafer equipment for material monitoring, placement, yield prediction, and yield management. A reticle (photomask) is inspected at various times to identify changes in the reticle over time. Reticle defects that change over time are related to wafer fabrication requalification, where the reticle is inspected to ensure that it is not contaminated during storage or use. One particularly memory-intensive inspection process called die-to-gold inspection involves imaging a relevant portion of a known clean substrate. The clean image is known as the “golden image” of the reticle. The golden image is typically taken immediately after the reticle is cleaned and verified with a die-to-database inspection. A die-to-database test is an optical comparison of a reticle (or part of a reticle) with a computer-rendered image of the design database used to make the reticle.

  Once the golden image is stored, subsequent images on the substrate are compared to the golden image. Any variation is identified as a change or contamination to the reticle.

  A golden image is on the order of 8 terabytes per reticle. A semiconductor production process may include 1000 reticles. The total storage capacity of a golden image on a single semiconductor wafer may exceed 8000 terabytes. 8000 terabytes of golden image data is expensive to store and use. In addition to the cost of maintaining sufficient storage media, the golden image may not be stored at the location where the inspection process takes place, so the golden image also has a data bandwidth for transmitting the golden image to the inspection site. It ’s also expensive. In addition, golden images may include images taken with both reflected and transmitted light, effectively doubling the amount of data.

  Data compression can reduce the total amount of storage capacity required, but has some advantages. A reduction from 1/5 to 1/10 is desirable, but cannot be achieved by compression alone.

  Alternatively, the reticle may be inspected with reference to a semiconductor design database used to produce the reticle. The semiconductor design database is a fully accurate reference that may be used to render the resulting reticle image. Although the semiconductor design database may not consume as much storage space as a series of golden images, the storage requirements are still enormous. A semiconductor design database can be more than 1 terabyte per single reticle, so semiconductor wafers that require 1000 reticles are 1000 terabytes to transfer the database from their storage location to the inspection site. It still requires storage and corresponding bandwidth. Furthermore, the rendering of semiconductor design databases is extremely computationally intensive and often requires a supercomputer.

  Another type of inspection process, cell-to-cell (cell-to-cell) inspection, is a mode in which repeated structures are locally compared to each other and any perceived differences are defective. Cell-to-cell inspection has long been used for both wafer inspection and reticle inspection. This modality says that the reference data is located very close to the test area, so the inspection tool does not need to be particularly stable and the stored reference image is not necessary to use this technique successfully Have advantages. Similar to cell-to-cell inspection, die-to-die inspection is an inspection mode in which identical dies on the same substrate are compared.

  Therefore, it would be advantageous to have a device that is suitable for performing a hybrid test to reduce the amount of data required during the die-to-golden and die-to-database tests.

  Accordingly, the present invention is directed to a novel method and apparatus for performing a hybrid test to reduce the amount of data required during a die-to-golden test and a die-to-database test.

  One embodiment of the present invention is a method for determining which portion of a reticle requires a golden image. The method may include identifying appropriate cell-to-cell test candidates and die-to-die test candidates. The method may include obtaining and storing a golden image for only those portions of the reticle that are not suitable for cell-to-cell and die-die inspection.

  Another embodiment of the present invention provides a die-to by identifying cell-to-cell inspection candidates and die-to-die inspection candidates in the reticle, and storing only golden images for other parts of the reticle. A method for reducing the amount of data required for a golden test. The method may include applying a data compression algorithm.

  Another embodiment of the present invention determines a portion of the reticle that is suitable for cell-to-cell or die-to-die inspection and performs a die-to-golden inspection on the remaining portion. Golden inspection apparatus. The apparatus may also use “aerial imaging” technology. The aerial imaging technique may be performed with multiple focus values.

  It is understood that both the foregoing summary and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and serve to explain the principles together with an overview.

  Numerous objects and advantages of the present invention will be better understood by those skilled in the art with reference to the accompanying drawings.

It is a block diagram of a reticle. 1 is a block diagram of a system suitable for performing a reticle hybrid inspection. FIG. 3 is a flowchart of a method for creating a reduced database for hybrid die-to-database testing. 6 is a flowchart of a method for performing a hybrid die-to-database test of a reticle with a reduced database. 3 is a flowchart of a method for creating a reduced golden image for hybrid die-to-golden inspection. 6 is a flowchart of a method for performing a hybrid die-to-golden inspection of a reticle with a reduced golden image.

  Reference will now be made in detail to the disclosed subject matter, which is illustrated in the accompanying drawings. The scope of the invention is limited only by the claims and includes many variations, modifications, and equivalents. For the purpose of clarity, technical material that is known in the technical fields related to the embodiments has not been described in detail so as not to unnecessarily obscure the description.

  Referring to FIG. 1, a block diagram of reticle 100 is shown. During lithographic fabrication, one or more reticles 100 are used to build electronic components on a semiconductor wafer through methods known in the art. The features on the reticle 100 that define these electronic components may be organized into groups called cells 102, 104, 106. Some cells 102, 104, 106 are two such cells, for example a first cell 102 or a second cell of the reticle 100 that is a properly aligned comparison of the first cell 102 and the second cell 104. It is possible to include identical components in the same orientation to account for defects or contamination in any of 104. In addition, the reticle 100 may also include cells 102, 104, 106 that are similar but not identical. Even though all three cells 102, 104, 106 may include substantially the same components with substantially the same orientation, a semiconductor fabrication process may include one cell, eg, the third cell 106, the other. May need to be slightly different compared to the first cell 102 and the second cell 104, for example. Processes such as optical proximity correction may change the design of certain cells to correct potential irregularities in the fabrication process. A comparison between the first cell 102 and the third cell 106 may indicate a defect even if both cells 102, 106 are properly fabricated according to the intended design (false defect).

  The reticle 100 may also be knitted into dies 108, 110, 114, 112, with each die 108, 110, 114, 112 being one or more other dies 108, 110, 114, on the reticle 100. 112 is substantially similar. If two or more dies 108, 110, 114, 112 are identical, a die-to-die inspection can be performed to identify changes in the reticle used to produce the die.

  Referring to FIG. 2, an apparatus for creating a reduced semiconductor design database or database image of reticle 100 for hybrid inspection and for performing a hybrid inspection of reticle 100 is shown. The apparatus may include a processor 204, a memory 206 connected to the processor 204, and a data storage 208 connected to the processor 204. The processor 204 may analyze the semiconductor design database to identify cells that are intended to have the same structure in design and are therefore suitable for cell-to-cell testing. Further, processor 204 may identify repetitive dies in reticle 100. Repeating dies may be suitable for die-to-die inspection. The processor 204 may then perform a die-to-database inspection of regions of the reticle 100 where cell-to-cell inspection and die-to-die inspection are not available. The processor 204 may create a map of an area that requires a die-to-database test, or the processor 204 may create a rendered image of the area from a semiconductor design database. The processor 204 may then store the resulting image or map in the data storage 208. In another embodiment, the processor 204 creates and stores a modified version of the semiconductor design database (reduced database) that includes only portions where cell-to-cell and die-to-die inspection are not available. May be. During the subsequent inspection process, the processor 204 may only need to retrieve and transfer the reduced map or image stored in the data storage 208, or the reduced database. The processor 204 may perform a cell-to-cell inspection on a region of a reticle for which a cell-to-cell inspection is appropriate. The processor may also perform a die-to-die inspection on areas of the reticle for which a die-to-die inspection is appropriate.

  When the processor 204 is connected to the semiconductor design database and further connected to the imaging device 202, the processor 204 reads the semiconductor design database and renders the areas identified in the map as requiring a die-to-database test. May be. This device may reduce storage load and bandwidth load for die-to-database inspection.

  Semiconductor wafer fabrication facilities often have many inspection tools to accommodate the amount of inspection processing capability desired during production. A single semiconductor design database repository connected to many of these inspection tools reduces the logistics burden of replicating the semiconductor design database and reduces the cost of the fleet level. Using the present invention, each test requires only a small portion of the entire semiconductor design database. Thus, a system designed to support high-speed transfer of the entire semiconductor design database should be able to handle multiple reduced database transfers. Such a system may require the addition of a computer “fetcher” server for each inspection tool.

  Alternatively, the apparatus of FIG. 2 may create one or more reduced golden images used in the hybrid inspection process. The apparatus may include a processor 204, a memory 206 connected to the processor 204, an imaging device 202 connected to the processor 204, and a data storage 208 connected to the processor 204. The processor 204 may capture a golden image of the reticle 100 and analyze the image in order to identify cells that are designed to have the same structure and are therefore suitable for cell-to-cell inspection. Such analysis may include autocorrelation analysis or any other procedure suitable for identifying cell-to-cell test candidates. Further, processor 204 may identify repetitive dies in reticle 100. Repeating dies may be suitable for die-to-die inspection. The processor 204 may then perform a die-to-golden inspection of areas of the reticle 100 where cell-to-cell inspection and die-to-die inspection are not available. The processor 204 may store on the data storage 208 a portion of the golden image (reduced golden image) for an area of the reticle 100 where cell-to-cell or die-to-die inspection is not available. . During the subsequent inspection process, the processor 204 may only need to retrieve and transfer the reduced golden image from the data storage 208. The die-to-golden inspection is necessary only for areas of the reticle 100 where no other inspection process is available. This device may reduce storage load and bandwidth load for die-to-golden inspection. The processor 204 may perform the cell-to-cell inspection on the region of the reticle 100 where the cell-to-cell inspection is appropriate. The processor may also perform a die-to-die inspection on an area of the reticle 100 where a die-to-die inspection is appropriate.

  During subsequent hybrid die-to-database or hybrid die-to-gold inspection, defects or contamination in the reticle 100 may be detected by cell-to-cell inspection, die-to-die inspection, or die-to-database / die- It may be identified as a variation during a to-golden test. Any defect or contamination location may be recorded to track the aging of the reticle 100.

  One possible problem when using cell-to-cell inspection is that there may be intentional very small variations in the structure of cells that are otherwise identical. For example, reticle model-based optical-proximity-correction (OPC) and extreme ultraviolet (EUV) reticle flare correction may result in very slight differences in the design of nearly repetitive patterns. These changes can include, for example, very small jogs in long straight lines without obvious purposes. An existing method for determining whether a region repeats enough to apply a cell-to-cell test uses the image itself. This means that slight design differences between cells can reveal defects more easily than intentional design features (false defects).

  The possibility of false defects may be reduced or eliminated by identifying cell-to-cell inspection candidates through analysis of the cell's semiconductor design database. The processor 204 may perform an analysis, such as an autocorrelation analysis, on the rendered image of the design database to identify cell-to-cell test candidates. The peaks in the autocorrelation can show repeating patterns of varying fidelity and size. There is no measurement noise for the rendered semiconductor design database. Alternatively, the semiconductor design database may include a hierarchy that identifies the location of the same feature. The processor 204 may then create a region map showing the cells identified as being suitable for cell-to-cell inspection. The processor 204 may also identify reference points from the semiconductor design database 208 and include these reference points in the region map so that the region map can be properly aligned with the actually fabricated reticle 100. The region map may be stored in the memory 206 or in the data storage 208. During the subsequent inspection process, the region map may identify regions that are appropriate for cell-to-cell inspection.

  The golden image storage space may be further reduced with data compression. Those skilled in the art will appreciate that basic lossless data compression can reduce storage demand by approximately 20-30%, but the actual compression depends on many factors. Data compression may result in some loss of data fidelity (quantization noise), but may have a second advantage. For example, if the processor 204 removes the two least significant bits of the 8-bit data stream, the 25% storage demand is immediately reduced. However, the data may also be more coarsely quantized. Coarse quantization can make data compression over noisy uniform fields more effective. Data fidelity loss is given by quantization noise from data loss. Quantization noise is uniform uncorrelated noise that adds quadrature to other noise sources. Coarse quantization may be useful for the data compression step if the required inspection sensitivity can still be achieved.

  Data storage demand may be further reduced by storing only reflected light images, not both reflected and transmitted light. By excluding transmitted light images, the demand for data storage is reduced by half. Similarly, images with larger pixel sizes may be used to reduce the amount of storage required by the square of the pixel ratio. Especially for reticles, aerial images similar to those created with a stepper may use relatively large (125 nm) pixels. Large pixels may indicate whether the change will have a printing impact on the wafer. In order to perform an aerial image examination, the imaging device 202 should match the contour of the stepper illumination and the contour of the imaging pupil. Larger pixel sizes can make “early detection” more difficult, but can also reduce sensitivity to focus changes. Storage savings can be five times higher. In addition, aerial imaging may be performed at multiple focus values, resulting in a full process window inspection that can find defects affecting printing somewhere in the stepper's focus process window. Certain defects that have predominantly phase rather than transmission effects can have a greater defocus printing effect than the best focus.

  The apparatus of FIG. 2 may also perform a hybrid die-to-golden test. If an area map based on the semiconductor design database is stored in the data storage 208, the processor 204 may read the area map. The region map may indicate a region of the reticle 100 that is suitable for cell-to-cell inspection. The processor 204 may then image the reticle 100 using the imaging device 202. The processor 204 may then align the reticle 100 region map and image in the correct orientation based on the corresponding reference points. The processor 204 may then perform a cell-to-cell test on the region of the reticle 100 that is identified as suitable for the cell-to-cell test by the region map. If the processor 204 identifies a defect or contamination based on a cell-to-cell inspection, the processor 204 may record the location of the defect or contamination in the data storage 208. The processor 204 may also perform a die-to-die inspection on the image of the reticle 100 in an area where the die-to-die inspection is appropriate. If the processor 204 identifies a defect or contamination based on a die-to-die inspection, the processor 204 may record the location of the defect or contamination in the data storage 208.

  In areas of the reticle 100 where cell-to-cell and die-to-die inspections are inappropriate, the processor 204 may retrieve the reduced golden image from the data storage 208. The reduced golden image may include only those portions of the reticle 100 that are not suitable for cell-to-cell inspection or die-to-die inspection. The processor 204 may then perform a die-to-golden test using the reduced golden image. If processor 204 identifies a defect or contamination based on a die-to-golden inspection, processor 204 may record the location of the defect or contamination in data storage 208.

  Although the above description has focused on inspection of reticle 100, those skilled in the art will appreciate that all of the same principles, processes, and structures may be applicable to semiconductor wafer inspection. One skilled in the art will further appreciate that the same principles and procedures may be applied to any number of images necessary to inspect all of the reticle 100 for a given semiconductor.

  Referring to FIG. 3, a flow chart for preparing a reduced database for use in a reticle hybrid inspection process is shown. The processor may parse the cell to identify valid cell-to-cell test regions 300. Cell analysis may include autocorrelation analysis of the image of the reticle, or other processes known in the art. Cell analysis may also include reading the semiconductor design database and rendering the semiconductor design database with high fidelity. In this embodiment, high fidelity refers to the noise level of the resulting image as compared to the image typically created by the inspection hardware during inspection.

  When the processor renders the semiconductor design database, the processor performs an autocorrelation analysis to determine the faithful repeat region of the semiconductor design database and discards the cell-to-cell match region based on the autocorrelation analysis threshold. May be. In some embodiments, such as when the processor is not currently inspecting, the processor may output a region map of valid cell-to-cell inspection regions. Alternatively, if the processor is currently inspecting, the processor identifies to perform cell-to-cell inspection without creating an area map or creating an area map as a temporary data structure. It is also possible to directly use the region thus created.

  Alternatively, there may be a “hierarchy” in the semiconductor design database that indicates a pattern that repeats correctly in the semiconductor design database. The pattern may be described in detail only once and there may be an indication of all the places where the pattern is located. The hierarchy is used as a means for compressing the semiconductor design database. The processor can parse the semiconductor design database with respect to the hierarchy used to determine a region that is faithfully repeated and therefore suitable for cell-to-cell inspection.

  The processor may also analyze the die to identify valid die-to-die inspection areas (302). The processor may then create a reduced database based on the semiconductor design database, excluding areas appropriate for either cell-to-cell or die-to-die inspection (304). . The processor may then store the reduced database in data storage (306).

  Referring to FIG. 4, a flowchart for using the reduced database in a hybrid inspection process is shown. A processor in the inspection apparatus may read a reduced database that identifies regions in the reticle that are appropriate for cell-to-cell and die-to-die inspection (400). The processor may then perform a cell-to-cell test of the region where the reduced database indicates that a cell-to-cell test is appropriate (402). The processor may then perform 404 a die-to-die inspection of the region where the reduced database indicates that the die-to-die inspection is appropriate. The processor may then perform a die-to-database test using the reduced database (406). The processor may record any area identified as having a time course based on either a cell-to-cell test, a die-to-die test, or a die-to-database test (408).

  Referring to FIG. 5, a flowchart for preparing a reduced golden image for use in a reticle hybrid inspection process is shown. The processor may analyze the cell to identify valid cell-to-cell inspection regions (500). Cell analysis may include autocorrelation analysis of the image of the reticle, or other processes known in the art. Cell analysis may also include reading the semiconductor design database and rendering the semiconductor design database with high fidelity. In this embodiment, high fidelity refers to the noise level of the resulting image as compared to the image typically created by the inspection hardware during inspection.

  Alternatively, there may be a “hierarchy” in the semiconductor design database that indicates a pattern that repeats correctly in the semiconductor design database. The pattern may be described in detail only once and there may be an indication of all the places where the pattern is located. The hierarchy is used as a means for compressing the semiconductor design database. The processor can parse the semiconductor design database with respect to the hierarchy used to determine a region that is faithfully repeated and therefore suitable for cell-to-cell inspection.

  The processor may also analyze the die to identify valid die-to-die inspection areas (502). The processor then obtains a golden image of the reticle (504) and is reduced based on the golden image, excluding areas appropriate for either cell-to-cell or die-to-die inspection. A golden image may be created 506. A golden image may be used when analyzing a cell-to-cell inspection candidate and a die-to-die inspection candidate based on the reticle image. In this case, the acquisition of the golden image may be performed before the analysis. Those skilled in the art will appreciate that this is good. The golden image and the reduced golden image may include a reflected light image or a transmitted light image. The processor may then compress (508) the reduced golden image. The processor may then store the reduced golden image in data storage (510).

  Referring to FIG. 6, a flowchart for using a reduced golden image in a hybrid inspection process is shown. A processor in the inspection apparatus may search for a reduced golden image of the area on the reticle that is inappropriate for cell-to-cell and die-to-die inspection, and indicate where such inspection is appropriate (600). ). The processor may then perform a cell-to-cell inspection of the region where the reduced golden image indicates that the cell-to-cell inspection is appropriate (602). The processor may then perform a die-to-die inspection of the region where the reduced golden image indicates that a die-to-die inspection is appropriate (604). The processor may then perform a die-to-golden test using the reduced golden image (606). The processor may record any area identified as having a time course based on either a cell-to-cell test, a die-to-die test, or a die-to-golden test (608).

  The methods and apparatus described herein provide the advantages of data storage over the prior art. A smaller amount of stored data may also reduce bandwidth usage associated with putting the data in an imaging computer connected to the examination station. The use of reduced bandwidth can help expedite inspections faster and can reduce the cost of building such inspection stations.

  Many of the invention and its attendant advantages will be understood by the foregoing description, without departing from the scope and spirit of the invention or without sacrificing all of the advantages of the material. It will be apparent that various changes may be made in the form, configuration, and arrangement of components. The forms described above are merely illustrative embodiments thereof, and it is the intent of the following claims to encompass and include such changes.

Claims (27)

An inspection device,
A processor;
A memory connected to the processor;
Computer-executable program code configured to execute on the processor;
The program code executable by the computer is
look including a portion of the semiconductor design database that is not suitable for at least one of the cell-to-cell inspection or die-to-die inspection, suitable for at least one cell-to-cell inspection or die-to-dei test Create a reduced database, excluding the semiconductor design database .
Storing the reduced database for reference during the wafer inspection process ;
An inspection device configured as follows.   The computer-executable program code is further configured to analyze the semiconductor design database to identify one or more regions suitable for cell-to-cell inspection. apparatus.   The apparatus according to claim 2, wherein the analysis of the semiconductor design database includes performing an autocorrelation analysis.   The apparatus according to claim 2, wherein analyzing the semiconductor design database includes performing hierarchical analysis.   The computer-executable program code coupled to the processor and configured to image a reticle, the computer-executable program code further configured to obtain an image of the reticle. Equipment.   6. The computer-executable program code is further configured to identify one or more regions suitable for cell-to-cell inspection based on an autocorrelation analysis of the reticle image. The device described. An inspection device,
A processor;
A memory connected to the processor;
An imaging device connected to the processor and configured to image a reticle;
Computer-executable program code configured to execute on the processor;
The program code executable by the computer is
A reticle that includes a portion of the reticle that is not suitable for at least one of cell-to-cell inspection or die-to-die inspection, and is suitable for at least one of cell-to-cell inspection or die-to-die inspection. Create a reduced golden image , excluding
Storing the reduced golden image for reference during the wafer inspection process ;
An inspection device configured as follows.   The apparatus of claim 7, wherein the computer executable program code is further configured to obtain a golden image of the reticle.   The computer-executable program code further analyzes the golden image to identify one or more regions appropriate for one of a cell-to-cell or die-to-die inspection. 9. The apparatus of claim 8, wherein the apparatus is configured as follows.   The apparatus of claim 9, wherein analyzing the golden image comprises performing an autocorrelation analysis.   10. The creation of the reduced golden image includes removing regions of the golden image that are identified as suitable for one of a cell-to-cell or die-to-die inspection. The device described in 1. An inspection device,
A processor;
A memory connected to the processor;
An imaging device connected to the processor and configured to image a reticle;
Computer-executable program code configured to execute on the processor;
The computer-executable program code is configured to retrieve a reference, the reference comprising:
Identifying at least one region of the reticle that is suitable for at least one of a cell-to-cell inspection or a die-to-die inspection;
including a portion of the reticle not suitable for at least one of cell-to-cell inspection or die-to-die inspection, and a reticle that is suitable for at least one of cell-to-cell inspection or die-to-die inspection. Reduced data, excluding portions, of one or more additional areas of the reticle and not suitable for at least one of cell-to-cell inspection or die-to-die inspection An inspection apparatus configured to provide reduced data suitable for performing an inspection of one or more additional regions.   The computer-executable program code is further configured to perform a cell-to-cell test of at least one region suitable for a cell-to-cell test identified by the reference. apparatus.   The apparatus of claim 13, wherein the computer-executable program code is further configured to record a defect or contamination location identified by the cell-to-cell inspection.   The computer-executable program code is further configured to perform a die-to-die inspection of at least one region suitable for a die-to-die inspection identified by the reference. apparatus.   The apparatus of claim 15, wherein the computer-executable program code is further configured to record a defect or contamination location identified by the die-to-die inspection.   The apparatus of claim 12, wherein the reference is a reduced database.   The apparatus of claim 12, wherein the reference is a reduced golden image. A method for creating a reference for hybrid inspection,
identifying at least one region of the reticle suitable for at least one of a cell-to-cell inspection or a die-to-die inspection;
identifying one or more additional regions of the reticle that are inappropriate for at least one of a cell-to-cell inspection or a die-to-die inspection;
Creating a reference,
Including
Said reference is
identifying the at least one region of the reticle suitable for at least one of a cell-to-cell inspection or a die-to-die inspection;
Create reduced data sufficient to inspect the one or more additional regions of the reticle that are inappropriate for at least one of cell-to-cell or die-to-die inspection The reduced data includes a portion of the reticle that is not suitable for at least one of a cell-to-cell inspection or a die-to-die inspection, and a cell-to-cell inspection or a die-to-die inspection. A method wherein a portion of the reticle that is suitable for at least one of the above is removed .   The method of claim 19, wherein the reference comprises a reduced database.   Identification of the at least one region suitable for at least one of cell-to-cell or die-to-die inspection performs one of autocorrelation analysis or hierarchical analysis on the semiconductor design database. 21. The method of claim 20, comprising:   The method of claim 19, wherein the reference comprises a reduced golden image.   23. The method of claim 22, further comprising compressing the reference.   The identification of the at least one region suitable for at least one of a cell-to-cell test or a die-to-die test comprises performing an autocorrelation analysis on the golden image. the method of. A method for creating a reference for hybrid inspection,
Retrieving a reference from a data storage element ,
Identifying at least one region of the reticle suitable for at least one of a cell-to-cell inspection or a die-to-die inspection based on the reference;
Performing at least one of a cell-to-cell inspection or a die-to-die inspection of the identified region;
Before by the image sharpness chicle compared with data contained in the reference, prior identified as unsuitable to at least one of the cell-to-cell inspection or die-to-die inspection crisp Perform defect / contamination inspection of one or more additional areas of the chickle;
And the reference is
Identifying the at least one region of the reticle suitable for at least one of the cell-to-cell inspection or the die-to-die inspection;
cell-to-cell inspection or die-to-die at least one sufficient to perform inspection of the one or more additional regions of inappropriate pre sharp chicle to a reduced data of the test The reduced data includes a portion of the reticle that is not suitable for at least one of a cell-to-cell inspection or a die-to-die inspection, and a cell-to-cell inspection or a die-to- A method wherein a portion of the reticle that is suitable for at least one of the dei tests is removed .   26. The method of claim 25, wherein the reference is a reduced database.   26. The method of claim 25, wherein the reference is a reduced golden image.

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