DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08/21/2024 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
The information disclosure statement (IDS) submitted on 11/26/2025 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are: “Wafer scanning module, configured for scanning,” “ an image sharpness calculation module, configured for obtaining a wafer image”, “a sharpness evaluation value calculation module, configured for obtaining a sharpness evaluation value,” “a sharpness evaluation value determination module, configured for determining whether the sharpness evaluation value” “detection result marking module, configured for marking a defect detection result “ in claim 17.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-4, 14, 15, 17-19 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Shemesh et al (Shemesh hereinafter US 20230114624 A1).
As per claim 1
Shemesh teaches A wafer defect detection method, comprising: scanning, by an electron-beam, a target defect detection region of a to-be-detected wafer to detect a defect of the target defect detection region, wherein the to-be-detected wafer has one or more defect detection regions (Paragraph [0043] “ at least one of the examination tools 120 can be an inspection tool (e.g., an optical inspection tool, a Scanning Electron Microscope (SEM), etc.) configured to scan a specimen (e.g., an entire wafer, an entire die or portions thereof) to capture inspection images for detection of potential defects on the specimen.”) obtaining a wafer image of the to-be-detected wafer, (Paragraph [0043] “…to capture inspection images for detection of potential defects on the specimen.”) calculating an image sharpness of the wafer image (Paragraph [0047] “The point of optimal focus can be found by executing a focus calibration…during which the examination tool scans through different focal planes (“focus ramp”), calculates a focus score for each image…”) obtaining a sharpness evaluation value of the wafer image based on the image sharpness of the wafer image (Paragraph [0047] The point of optimal focus…focus score for each image…) determining whether the sharpness evaluation value of the wafer image meets a preset condition (“Paragraph [0088] “it is of interest to identify which images in the image set are considered to be out of focus, while which ones are considered to be in focus, rather than determining the absolute degree of focus of each image in the set. Accordingly, it is needed to determine a focus threshold which can be used to distinguish the out of focus images from the in-focus images. “) marking a defect detection result of the to-be-detected wafer as an unreliable detection result when the sharpness evaluation value of the wafer image fails to meet the preset condition. (Paragraph [0094] “The images having the focus scores below the focus threshold can be labeled with the ground truth label of defocused (or out of focus), while the images having the focus scores above (or equal to) the focus threshold can be labeled with the ground truth label of focused (or in focus)” Examiner notes that an “Out of focus” image constitutes an unreliable detection)
As per claim 2
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches wherein obtaining the sharpness evaluation value of the wafer image based on the image sharpness of the wafer image comprises: calculating a sharpness difference value between the image sharpness of the wafer image and a preset standard sharpness of the wafer image to obtain the sharpness evaluation value of the wafer image (Paragraph [0095] “the focus score for an image can be calculated using different focus measures assessing the degree of sharpness, or degree of focus of an image, and the present disclosure is not limited to a specific focus score calculation…gradient-based focus measure, which is based on the gradient or approximations of the first derivatives of the image, can be used for calculating the focus score. This focus measure follows the assumption that focused images present sharper edges than blurred ones. Thus, the energy of the gradient can be exploited in order to estimate the degree of focus. Similarly, a Laplacian-based focus measure, which is based on the second derivative of the image, can also be used. By way of another example, a statistics-based focus measure, which is based on text descriptors of the image, can be used. This focus measure follows the assumption that a defocused image can be interpreted as a texture whose smoothness increases for increasing levels of defocus. Paragraph [0097] “the initial values of the model parameters of a ML model (e.g., a DNN) can be selected prior to training, and can be further iteratively adjusted or modified during training to achieve an optimal set of weighting and/or threshold values in a trained DNN. After each iteration, a difference can be determined between the actual output produced by DNN and the target output associated with the respective training set of data. The difference can be referred to as an error value.”) wherein the sharpness evaluation value of the wafer image fails to meet the preset condition when the sharpness evaluation value of the wafer image is greater than or equal to a first sharpness difference threshold. (Paragraph [0094] Once the focus threshold is derived, it can be applied to the set of images obtained for the given specimen, e.g., by comparing the focus scores of the images in the set with the focus threshold…if the focus score is defined otherwise, e.g., a smaller score indicates a better focus degree, then the images having the focus scores above (or equal to) the focus threshold can be labeled with the ground truth label of defocused (or out of focus), while the images having the focus scores below the focus threshold can be labeled with the ground truth label of focused (or in focus). Examiner considers “Defocused” labeling as being a failing condition. )
As per claim 3
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches wherein when the sharpness evaluation value of the wafer image fails to meet the preset condition, the defect of the to-be-detected wafer is stopped to be detected. (Figure 2. Whenever the first, second, or any image is not in focus, that image does not proceed to the defect examination stage.)
As per claim 4
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches after obtaining the sharpness evaluation value of the wafer image, the method further comprises: outputting the sharpness evaluation value of the wafer image to a statistical process control system, to make the statistical process control system to mark the defect detection result of the to-be-detected wafer as the unreliable detection result when the sharpness evaluation value of the wafer image fails to meet the preset condition. (Paragraph [0095] “ the focus score for an image can be calculated using different focus measures assessing the degree of sharpness, or degree of focus of an image, and the present disclosure is not limited to a specific focus score calculation… a statistics-based focus measure, which is based on text descriptors of the image, can be used. This focus measure follows the assumption that a defocused image can be interpreted as a texture whose smoothness increases for increasing levels of defocus.” )
As per claim 14
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches obtaining a focus image of the to-be-detected wafer (Figure 4) calculating an image sharpness of the focus image (Figure 4) obtaining a sharpness evaluation value of the focus image based on the image sharpness of the focus image (Paragraph [0095] “the focus score for an image can be calculated using different focus measures assessing the degree of sharpness, or degree of focus of an image, and the present disclosure is not limited to a specific focus score calculation”) determining whether the sharpness evaluation value of the focus image meets the preset condition (Paragraph [0094] “ Once the focus threshold is derived, it can be applied to the set of images obtained for the given specimen, e.g., by comparing the focus scores of the images in the set with the focus threshold. “) stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the focus image fails to meet the preset condition. (Paragraph [0040] “System 101 is designed and configured to examine the focus of each FOV during scanning, and trigger a focus calibration process when it is found that an image is out of focus, as detailed below.” Shemesh’s focus examination is done while scanning for defects is happening Once a focus score does not meet focus threshold a focus calibration process is initiated effectively halting scanning for the calibration).
As per claim 15
Shemesh teaches obtaining the sharpness evaluation value of the focus image based on the image sharpness of the focus image comprises: calculating a sharpness difference value between the image sharpness of the focus image and a preset standard sharpness of the focus image, to obtain the sharpness evaluation value of the focus image (Paragraph [0095] “the focus score for an image can be calculated using different focus measures assessing the degree of sharpness, or degree of focus of an image,” Paragraph [0097] “a difference can be determined between the actual output produced by DNN and the target output associated with the respective training set of data. The difference can be referred to as an error value”) wherein the sharpness evaluation value of the focus image fails to meet the preset condition when the sharpness evaluation value of the focus image is greater than or equal to a third sharpness difference threshold. (Paragraph [0094] “Once the focus threshold is derived, it can be applied to the set of images obtained for the given specimen, e.g., by comparing the focus scores of the images in the set with the focus threshold…the images having the focus scores above (or equal to) the focus threshold can be labeled with the ground truth label of defocused (or out of focus)).
As per claim 17
Claim 17 is the parallel device claim to method claim 1 and will be rejected under the same premise.
As per claim 18
Shemesh teaches all claim limitations rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches An electron-beam scanning device, comprising: one or more processors; and a memory, for storing one or more computer programs; wherein the one or more computer programs, when executed by the one or more processors, cause the one or more processors to implement the wafer defect detection method according to claim 1. (Figure 1.)
As per claim 19
Shemesh teaches all claim limitations rejected in claim 1’s 102 rejection. See claim 1’s 102 rejection.
Shemesh teaches A non-transient computer-readable storage medium, on which computer-readable instructions are stored, the computer-readable instructions when executed by a processor of a computer, cause the computer to implement the wafer defect detection method according to claim 1. (Figure 1, Paragraph [0020] “ In accordance with other aspects of the presently disclosed subject matter, there is provided a non-transitory computer readable medium comprising instruction that, when executed by a computer, cause the computer to perform a method of runtime defect examination on a semiconductor specimen, the method comprising…”
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Shemesh et al (Shemesh hereinafter US 20230114624 A1 ) in view of Konecky et al (Konecky hereinafter KR 20170132841 “A Sub-pixel And Sub-resolution Localization Of Defects On Patterned Wafers”)
As per claim 6
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection
Shemesh does not teach, wherein the wafer image is an image of a wafer region that is located outside the target defect detection region on the to-be-detected wafer, has a distance from the target defect detection region less than a first preset distance, and is not scanned by the electron-beam.
Konecky teaches wherein the wafer image is an image of a wafer region that is located outside the target defect detection region on the to-be-detected wafer, has a distance from the target defect detection region less than a first preset distance (DESCRIPTION-OF-EMBODIMENTS: The computer subsystem (s) is further configured to determine whether the defect is a DOI or a news based on the determined distance….The step of determining whether the defect is a DOI or a Newswise includes applying a threshold to the determined distance, determining that the defect is a DOI if the determined distance is less than the threshold, “) and is not scanned by the electron-beam. (DESCRIPTION-OF-EMBODIMENTS: “In this manner, distance thresholds (or thresholds) can be set to maximize the DOI capture rate while minimizing emissions. For example, a distance threshold can be set and an event that is too far away from the expected location can be classified as Newsworthy. “In this way, each ROI may correspond to a different known location of interest. As further described herein, a defect signal originating outside these areas can be eliminated as not corresponding to a defect of interest, thereby greatly reducing emissions and increasing sensitivity.” Examiner considers eliminating areas outside the region of interest and resultant of reducing emissions means these areas were not scanned by the electron beam).
Accordingly, a person of ordinary skill in the art, at the time this invention was effectively filed would have found it obvious to modify Shemesh’s wafer defect detection pipeline with Konecky’s concept of identifying an area with a distance less than a preset distance from the target defect detection region and halting electron beam scanning. A person of ordinary skill in the art would be motivated to do so because they are aware that in semiconductor fabrication, having the least amount of electron beam emission is desirable. This reduces unneeded wafer damage and charging at areas that are not needed for examination.
Claim 7 are rejected under 35 U.S.C. 103 as being unpatentable over Shemesh et al (Shemesh hereinafter US 20230114624 A1) in view of Wienecke at al (Wienecke hereinafter EP 1712898 A1 “Method To Inspect A Wafer”)
As per claim 7
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection.
Shemesh teaches wherein before scanning, by the electron-beam, the target defect detection region of the to-be-detected wafer, the method further comprises: obtaining a brightness and contrast image of the to-be-detected wafer (Figure 5)
Shemesh does not teach obtaining a gray scale distribution of the brightness and contrast image; obtaining a gray scale distribution evaluation value of the brightness and contrast image based on the gray scale distribution of the brightness and contrast image; determining whether the gray scale distribution evaluation value meets the preset condition; and stopping to detect the defect of the to-be-detected wafer when the gray scale distribution evaluation value fails to meet the preset condition.
Wienecke teaches obtaining a brightness and contrast image of the to-be-detected wafer (Figure 1 and Figure 2. Examiner notes that all digital images have brightness and contrast) obtaining a gray scale distribution of the brightness and contrast image (“FIG. 5 shows a reference histogram 93 of a reference wafer for the gray values.”) obtaining a gray scale distribution evaluation value of the brightness and contrast image based on the gray scale distribution of the brightness and contrast image (“FIG. 5 shows a reference histogram 93 of a reference wafer for the gray values) ; determining whether the gray scale distribution evaluation value meets the preset condition (“Creation of a histogram from the image for at least the light and / or dark area. - Subtraction of the analogous areas of histogram and reference histogram. Comparison of whether the respective absolute difference values exceed the threshold values.”) stopping to detect the defect of the to-be-detected wafer when the gray scale distribution evaluation value fails to meet the preset condition. (It is expediently provided that one or more threshold values are defined for the dependency for the resumption.…If the thresholds are exceeded, the image is assessed as faulty and a resumption of the image is made…” The failure of this threshold preset condition is beneath the threshold value. When it is beneath the threshold value there is no resumption of analysis).
Accordingly, a person of ordinary skill in the art at the time this invention was effectively filed would have found it obvious to modify Shemesh’s pipeline with Wolter’s concept of using a grayscale distribution in concordance with a predefined criterion, in order to control the electron beam emission. A person of ordinary skill in the art would be motivated to do this because they are aware deviations from an expected distribution allow an indication that imaging conditions have changed and the defect detections may become unreliable. A person of ordinary skill in the art is aware that defect detection usually relies on intensity differences, edge contrast and or pattern contrast. They are aware if contrast becomes unreliable detection performance drops. Because of that fact a person of ordinary skill in the art would be made aware that histogram based evaluation enables an objective direction for determining whether enough contrast exists for accurate defect detection. A person of ordinary skill in the art would also want to see the determination of the thresholding in order to prevent image quality deficiencies from affecting the actual defect review pipeline downstream.
Claims 11 and 16 rejected under 35 U.S.C. 103 as being unpatentable over Shemesh et al (Shemesh hereinafter US 20230114624 A1) in view of Wienecke at al (Wienecke hereinafter EP 1712898 A1 “Method To Inspect A Wafer”) in further view of Watanabe et al (Watanabe hereinafter US 20030006371 A1)
As per claim 11
Shemesh and Wienecke teach all claim limitations previously rejected in claim 7’s 103 rejection
Shemesh nor Wienecke teach wherein when the gray scale distribution evaluation value meets the preset condition, the method further comprises: obtaining an astigmation image of the to-be-detected wafer, and calculating an image sharpness of the astigmation image; obtaining a sharpness evaluation value of the astigmation image based on the image sharpness of the astigmation image; determining whether the sharpness evaluation value of the astigmation image meets the preset condition; stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the astigmation image fails to meet the preset condition; and performing a step of scanning, by the electron-beam, the target defect detection region of the to-be-detected wafer when the sharpness evaluation value of the astigmation image meets the preset condition.
Watanabe teaches obtaining an astigmation image of the to-be-detected wafer (Figure 10. Paragraph [0052] FIG. 4 includes top views of a pattern for focus and astigmatism correction according to embodiment. FIG. 5 is a flowchart representing picture processing carried out by a picture-processing circuit employed in the charged-particle beam apparatus shown in FIG. 1 to compute astigmatism and focus correction quantities; ) and calculating an image sharpness of the astigmation image (Paragraph [0079] The astigmatism & focus-correction-quantity-computation picture-processing unit 53 then finds degrees of directional sharpness.”) obtaining a sharpness evaluation value of the astigmation image based on the image sharpness of the astigmation image (Paragraph [0108] the directional sharpness d.theta. is found by carrying out a directional-differentiation process on a particle picture detected by the particle detector 16. The directional-differentiation process is carried out by convolution of a mask like one shown in the figure on the picture. Then, a sum of squares of values at all points on the picture of a differentiation is computed to be used as the directional sharpness d.theta.. Paragraph [0121] “the center position p.theta. is found as the center of gravity of points representing values greater than a predetermined threshold. A proper method can be selected.” ) determining whether the sharpness evaluation value of the astigmation image meets the preset condition (Figure 13. Paragraph [0127] “Then, a threshold value is found as a product of the maximum value and a coefficient a not greater than 1. The middle point of the directional sharpness is finally found as a center of gravity of hatched areas enclosed by the graph's portions representing sharpness greater than the threshold value and a horizontal line representing the threshold value.”) stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the astigmation image fails to meet the preset condition performing a step of scanning, by the electron-beam, the target defect detection region of the to-be-detected wafer when the sharpness evaluation value of the astigmation image meets the preset condition. (Figure 18, Paragraph [0112] “ FIG. 18 is a flowchart representing processing to correct astigmatism for a case in which the directional sharpness is computed by adopting the method shown in FIG. 17) Paragraph [0161] “ In addition, the present invention also exhibits another effect that inspection or measurement can be carried out automatically with a high degree of stability…including the pattern in a scanning operation wherein the converged charged-particle beam has been subjected to high-speed and high-precision automatic adjustment of astigmatism and a focus…” The adjustment is automatic as scanning is done. Although considered “high-speed” scanning must stop to perform adjustment when sharpness is below a threshold.)
Accordingly, a person of ordinary skill in the art at the time this invention was effectively filed would have found it obvious to modify the previously modified Shemesh/Wienecke methodology and incorporate Watanabe’s concept of making a sharpness value based on image astigmatism. A person of ordinary skill in the art would have been motivated to evaluate the sharpness of an astigmatation image after confirming through the Shemesh/Wienecke pipeline an acceptable brightness and contrast in order to verify proper focus and correct astigmatition before defect inspection. Thereby improving the accuracy and reliability of wafer detection. Shemesh notes that “The examination processes are generally performed on the output images acquired by the examination tools. Images with degraded quality in various aspects, such as defocused images, when being used for examination of the semiconductor specimen, may impact the examination results.” (Paragraph [0006]) and that “When the acquired image is not in its optimal focus, the image becomes blurred and the resolution deteriorates, which has a negative impact on defect detection of advanced semiconductor processes. Such defocus effect can lead to an increasing inability to accurately detect and classify defects,” (Paragraph [0050]) A person of ordinary skill is aware that wafer astigmatism also negatively effects defect detection by introducing blur. Shemesh also notes that “the focus plane of the examination tool can be adjusted (402) to a plurality of focus points along a focus axis. By way of example, the focus plane can be adjusted by mechanically moving a placement stage of the semiconductor specimen (e.g., to different heights as relative to the detector of the tool). By way of another example, the focus plane can be adjusted by electrically changing a landing energy of an electron beam of the examination tool (e.g., to different intensities which can result in different degrees of focus in the images).” Watanabe offers an automatic path to adjustment.
As per claim 16
Shemesh teaches all claim limitations of claim 14 in claim 14’s 102 rejection. See claim 14
Wienecke teaches obtaining a brightness and contrast image of the to-be-detected wafer ((Figure 1 and Figure 2. Examiner notes that all visible images have brightness and contrast), obtaining a gray scale distribution of the brightness and contrast image (“FIG. 5 shows a reference histogram 93 of a reference wafer for the gray values.”) obtaining a gray scale distribution evaluation value of the brightness and contrast image based on the gray scale distribution of the brightness and contrast image((“FIG. 5 shows a reference histogram 93 of a reference wafer for the gray values)) determining whether the gray scale distribution evaluation value meets the preset condition (“Creation of a histogram from the image for at least the light and / or dark area. - Subtraction of the analogous areas of histogram and reference histogram. Comparison of whether the respective absolute difference values exceed the threshold values.”) stopping to detect the defect of the to-be-detected wafer when the gray scale distribution evaluation value fails to meet the preset condition ((It is expediently provided that one or more threshold values are defined for the dependency for the resumption.…If the thresholds are exceeded, the image is assessed as faulty and a resumption of the image is made…” The failure of this threshold preset condition is beneath the threshold value. When it is beneath the threshold value there is no resumption of analysis).
Watanabe teaches obtaining an astigmation image of the to-be-detected wafer (Figure 10. Paragraph [0052] FIG. 4 includes top views of a pattern for focus and astigmatism correction according to embodiment. FIG. 5 is a flowchart representing picture processing carried out by a picture-processing circuit employed in the charged-particle beam apparatus shown in FIG. 1 to compute astigmatism and focus correction quantities; ) and calculating an image sharpness of the astigmation image (Paragraph [0079] The astigmatism & focus-correction-quantity-computation picture-processing unit 53 then finds degrees of directional sharpness.”) obtaining a sharpness evaluation value of the astigmation image based on the image sharpness of the astigmation image; (Paragraph [0108] the directional sharpness d.theta. is found by carrying out a directional-differentiation process on a particle picture detected by the particle detector 16. The directional-differentiation process is carried out by convolution of a mask like one shown in the figure on the picture. Then, a sum of squares of values at all points on the picture of a differentiation is computed to be used as the directional sharpness d.theta.. Paragraph [0121] “the center position p.theta. is found as the center of gravity of points representing values greater than a predetermined threshold. A proper method can be selected.” ) determining whether the sharpness evaluation value of the astigmation image meets the preset condition (Figure 13. Paragraph [0127] “Then, a threshold value is found as a product of the maximum value and a coefficient a not greater than 1. The middle point of the directional sharpness is finally found as a center of gravity of hatched areas enclosed by the graph's portions representing sharpness greater than the threshold value and a horizontal line representing the threshold value.”) stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the astigmation image fails to meet the preset condition; and performing a step of scanning, by the electron-beam, the target defect detection region of the to-be-detected wafer when the sharpness evaluation value of the astigmation image meets the preset condition. (Figure 18, Paragraph [0112] “ FIG. 18 is a flowchart representing processing to correct astigmatism for a case in which the directional sharpness is computed by adopting the method shown in FIG. 17) Paragraph [0161] “ In addition, the present invention also exhibits another effect that inspection or measurement can be carried out automatically with a high degree of stability…including the pattern in a scanning operation wherein the converged charged-particle beam has been subjected to high-speed and high-precision automatic adjustment of astigmatism and a focus…” The adjustment is automatic as scanning is done. Although considered “high-speed” scanning must stop to perform adjustment when sharpness is below a threshold.)
In regards to “when the gray scale distribution evaluation value meets the preset condition, obtaining an astigmation image…” in a combined teaching within the Shemesh/Wienecke/Watanabe pipeline, a person of ordinary skill in the art would know to implement this into the method to isolate optical column misalignment from the actual physical defects.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Shemesh et al (Shemesh hereinafter US 20230114624 A1) in view of Watanabe et al (Watanabe hereinafter US 20030006371 A1)
As per claim 13
Shemesh teaches all claim limitations previously rejected in claim 1’s 102 rejection.
Shemesh does not teach obtaining an astigmation image of the to-be-detected wafer, and calculating an image sharpness of the astigmation image; obtaining a sharpness evaluation value of the astigmation image based on the image sharpness of the astigmation image; determining whether the sharpness evaluation value of the astigmation image meets the preset condition; and stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the astigmation image fails to meet the preset condition.
Watanabe teaches obtaining an astigmation image of the to-be-detected wafer (Figure 10. Paragraph [0052] FIG. 4 includes top views of a pattern for focus and astigmatism correction according to embodiment. FIG. 5 is a flowchart representing picture processing carried out by a picture-processing circuit employed in the charged-particle beam apparatus shown in FIG. 1 to compute astigmatism and focus correction quantities; ) and calculating an image sharpness of the astigmation image (Paragraph [0079] The astigmatism & focus-correction-quantity-computation picture-processing unit 53 then finds degrees of directional sharpness.”) obtaining a sharpness evaluation value of the astigmation image based on the image sharpness of the astigmation image (Paragraph [0108] the directional sharpness d.theta. is found by carrying out a directional-differentiation process on a particle picture detected by the particle detector 16. The directional-differentiation process is carried out by convolution of a mask like one shown in the figure on the picture. Then, a sum of squares of values at all points on the picture of a differentiation is computed to be used as the directional sharpness d.theta.. Paragraph [0121] “the center position p.theta. is found as the center of gravity of points representing values greater than a predetermined threshold. A proper method can be selected.” ) determining whether the sharpness evaluation value of the astigmation image meets the preset condition (Figure 13. Paragraph [0127] “Then, a threshold value is found as a product of the maximum value and a coefficient a not greater than 1. The middle point of the directional sharpness is finally found as a center of gravity of hatched areas enclosed by the graph's portions representing sharpness greater than the threshold value and a horizontal line representing the threshold value.”) stopping to detect the defect of the to-be-detected wafer when the sharpness evaluation value of the astigmation image fails to meet the preset. (Figure 18, Paragraph [0112] “ FIG. 18 is a flowchart representing processing to correct astigmatism for a case in which the directional sharpness is computed by adopting the method shown in FIG. 17) Paragraph [0161] “ In addition, the present invention also exhibits another effect that inspection or measurement can be carried out automatically with a high degree of stability…including the pattern in a scanning operation wherein the converged charged-particle beam has been subjected to high-speed and high-precision automatic adjustment of astigmatism and a focus…” The adjustment is automatic as scanning is done. Although considered “high-speed” scanning must stop to perform adjustment when sharpness is below a threshold.)
Accordingly, a person of ordinary skill in the art would have been motivated to modify Shemesh’s workflow with Watanabe’s concept of making a sharpness value based on image astigmatism and thresholding the action of the electron beam based on the value. A person of ordinary skill in the art would have been motivated to do so because evaluating the sharpness of an astigmatized image prior to scanning a target detection region is desirable because astigmatism induced blur will obscure and distort wafer defects. A person of ordinary a skill in the art would want to verify sufficient image sharpness before inspection to improve defect recognition fidelity and reduce false defect determinations.
Allowable Subject Matter
Claim 5, 8-10, and 12 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. MUELLER et al US 20200118786 A1, KRIS et al US 20220207681 A1, Takagi US 20130070078 A1
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/SHANE WRENSFORD CODRINGTON/Examiner, Art Unit 2667
/MATTHEW C BELLA/Supervisory Patent Examiner, Art Unit 2667
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