DETAILED ACTION
This Office action is in response to the amendment filed on September 2nd, 2025. Claims 1-4 and 6-16 are pending.
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 .
Claim Rejections - 35 USC § 103
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(s) 1-4, 7-13, and 15-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 2016/0056014 (Yamamoto et al.) in view of the teachings of US 2015/0002652 (Takasugi et al.).
Regarding claim 1, Yamamoto et al. discloses a charged particle beam system comprising: a charged particle beam irradiating unit that irradiates a sample with charged particle beams (fig. 1, element 1); a detector that detects a signal from the sample (fig. 1, elements 9 & 10); and a computer system, including a graphical user interface, that measures an overlay shift amount between a first layer of the sample and a second layer lower than the first layer based on output of the detector (fig. 1, element 19, wherein ‘A GUI, which will be described later, is displayed on the non-illustrated monitor.’ P 33), wherein the computer system is configured to generate a plurality of first images with respect to the first layer and a plurality of second images with respect to the second layer based on the output of the detector (fig. 4A, step 37), from among the plurality of first images and the plurality of second images, generate a first added image by adding the first images by a first added number of images and generate a second added image by adding the second images by a second added number of images (fig. 4C, steps 38e & 38g), and measure an overlay shift amount between the first layer and the second layer based on the first added image and the second added image (fig. 4C, step 38j), wherein the computer system is configured to be able to determine an initial image of the first added image for adding among a plurality of captured images, in addition to the first added number of images and the second added number of images (inherent in the adding step, an initial image must be chosen to begin addition).
Yamamoto et al. does not disclose a graphical user interface wherein whether to perform drift correction is selectable via the graphical user interface, and in a case in which drift correction is selected, the graphical user interface provides a drift correction setting screen in which drift correction settings, including a pixel range used for detecting a drift amount with respect to the captured images, an added number of images with respect to images which are a drift correction target, and a range of the images to be the drift correction target, are separately selectable for the first layer and the second layer, and wherein a first range of the first added number of images and a second range of the second added number of images are selectable via the graphical user interface, such that the first range begins at any of the first images and the second range begins at any of the second images. Yamamoto et al. also does not disclose the first added number of images is 2 and the second added number of images is 256.
Takasugi et al. discloses a charged particle beam system with a computer system configured to generate added images by generating a plurality of images and adding specified number of them (‘The number of images for forming a single completed image (frame integration number) may be arbitrarily set, and thus a proper value is set in view of conditions such as secondary electron generation efficiency.’ P 49) and includes a graphical user interface wherein whether to perform drift correction is selectable via the graphical user interface, and in a case in which drift correction is selected, the graphical user interface provides a drift correction setting screen in which drift correction settings, including a pixel range used for detecting a drift amount with respect to the captured images (fig. 8).
It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify Yamamoto et al. to include the drift correction GUI of Takasugi et al. so that the blurring effect of drift could be corrected if needed, as disclosed by Takasugi et al. (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction.’ P 2).
It would further have been obvious to make an added number of images with respect to images which are a drift correction target, and a range of the images to be the drift correction target, separately selectable for the first layer and the second layer, and to use a large number of images for the second added number because this is known to increase the signal to noise ratio at the expense of increasing charge up blurring (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction. In order to decrease the influence of drift, the number of integrated frames may be decreased so as to shorten the integration time; however, this makes it difficult to obtain a sufficient S/N ratio.’ P 2) and it is well-known that backscattered electron images have a lower resolution than secondary electron images. On the other hand, secondary electron images are more prone to charging effects, and would be optimized at a small number of frames. The particular values of 2 and 256 do not appear to serve any particular purpose beyond the reasons for small and large numbers discussed above.
Finally, it would have been obvious to a person having ordinary skill in the art at the time the application was file to use the graphical user interface to allow the user to select a first range of the first added number of images and a second range of the second added number of images such that the first range begins at any of the first images and the second range begins at any of the second images to allow the user greater flexibility in choosing which images are included in the final integrations based on changing imaging conditions.
Regarding claim 2, Yamamoto et al. in view of Takasugi et al. disclose the charged particle beam system according to claim 1, wherein the computer system is configured to perform a matching process between a first template image and the first added image (‘Further, an image is cut out from the added image 136 for upper-layer pattern at a position corresponding to the cut out image 152 to create an image 153 having the same portion as that of the template 69.’ P 78), perform a matching process between a second template image and the second added image (‘First, a position 151 in the added image 146 for lower-layer pattern that coincides with the template 70 is calculated’ P 78), and measure an overlay shift amount between the first layer and the second layer according to results of the matching processes (‘The superposition misalignment amount is calculated, according to the following expressions, from the pixel-based center position 154 (Mx, My) of the upper-layer pattern, pixel-based center position 156 (Nx, Ny) of the lower-layer pattern, and the pixel size S.’ P 79).
Regarding claim 3, Yamamoto et al. in view of Takasugi et al. disclose the charged particle beam system according to claim 1, wherein the computer system generates the first images based on information of secondary electrons generated by irradiating the sample with the charged particle beams and generates the second images based on information of backscattered electrons generated by irradiating the sample with the charged particle beams (‘For example, for the upper-layer pattern, a signal from a secondary electron detector (SE detector) by which an edge portion is clearly imaged is used, while for the lower-layer pattern, a signal from a reflected electron detector (BSE detector) by which material contrast is easily obtained is used.’ P 50).
Regarding claim 4, Yamamoto et al. in view of Takasugi et al. disclose the charged particle beam system according to claim 1, wherein the computer system is configured to set the first added number of images and the second added number of images (Takasugi et al., ‘The number of images for forming a single completed image (frame integration number) may be arbitrarily set, and thus a proper value is set in view of conditions such as secondary electron generation efficiency.’ P 49). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the apparatus of Yamamoto et al. to allow for setting of the first and second number of added images as in Takasugi et al. so that the number could be set differently for different imaging conditions.
Regarding claim 7, Yamamoto et al. in view of Takasugi et al. disclose the charged particle beam system according to claim 1, wherein the computer system generates the first added image and the second added image by adding images after drift correction for reducing an influence due to drift (Takasugi et al., fig. 2, step S2011). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the system of Yamamoto et al. to include the drift correction of Takasugi et al. to reduce blur from drift, a problem with image integration disclosed in Takasugi et al. (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction.’ P 2).
Regarding claim 8, Yamamoto et al. in view of Takasugi et al. disclose the the claimed invention except for generating a plurality of intermediate images by adding the second images for each third number of images smaller than the second added number of images, and the drift correction is performed according to a shift amount between the plurality of intermediate images. However, it would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the drift correction method of Takasugi et al. in this manner to reduce the computational complexity, as forming intermediate images and performing drift correction in this manner requires looping through the drift correction steps fewer times.
Regarding claim 9, Yamamoto et al. discloses an overlay shift amount measurement method of measuring an overlay shift amount between different layers of a sample based on a signal detected by a detector by irradiating the sample with charged particle beams, the method comprising: a step of generating a plurality of first images with respect to a first layer of the sample and a plurality of second images with respect to a second layer lower than the first layer based on output of the detector (fig. 4A, step 37); a step of generating, from among the plurality of first images and the plurality of second images, a first added image by adding the first images by a first added number of images and generating a second added image by adding the second images by a second added number of images (fig. 4C, steps 38e & 38g); and a step of measuring an overlay shift amount between the first layer and the second layer based on the first added image and the second added image (fig. 4c, step 38j); and a step of determining an initial image of the first added image for adding among a plurality of captured images, in addition to the first added number of images and the second added number of images (inherent in the generation of the added images, initial images must be determined in order to do this).
Takasugi et al. discloses a charged particle beam system with a computer system configured to generate added images by generating a plurality of images and adding specified number of them (‘The number of images for forming a single completed image (frame integration number) may be arbitrarily set, and thus a proper value is set in view of conditions such as secondary electron generation efficiency.’ P 49) and includes a graphical user interface wherein whether to perform drift correction is selectable via the graphical user interface, and in a case in which drift correction is selected, the graphical user interface provides a drift correction setting screen in which drift correction settings, including a pixel range used for detecting a drift amount with respect to the captured images (fig. 8).
It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify Yamamoto et al. to include the drift correction GUI of Takasugi et al. so that the blurring effect of drift could be corrected if needed, as disclosed by Takasugi et al. (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction.’ P 2).
It would further have been obvious to make an added number of images with respect to images which are a drift correction target, and a range of the images to be the drift correction target, separately selectable for the first layer and the second layer, and to use a greater number of images for the second added number because this is known to increase the signal to noise ratio at the expense of increasing charge up blurring (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction. In order to decrease the influence of drift, the number of integrated frames may be decreased so as to shorten the integration time; however, this makes it difficult to obtain a sufficient S/N ratio.’ P 2) and it is well-known that backscattered electron images have a lower resolution than secondary electron images. On the other hand, secondary electron images are more prone to charging effects, and would be optimized at a smaller number of frames. The particular values of 2 and 256 do not appear to serve any particular purpose beyond the reasons for small and large numbers discussed above.
Finally, it would have been obvious to a person having ordinary skill in the art at the time the application was file to use the graphical user interface to allow the user to select a first range of the first added number of images and a second range of the second added number of images such that the first range begins at any of the first images and the second range begins at any of the second images to allow the user greater flexibility in choosing which images are included in the final integrations based on changing imaging conditions.
Regarding claim 10, Yamamoto et al. in view of Takasugi et al. disclose the overlay shift amount measurement method according to claim 9, further comprising: a step of performing a matching process between a first template image and the first added image and performing a matching process between a second template image and the second added image (‘First, a position 151 in the added image 146 for lower-layer pattern that coincides with the template 70 is calculated … Further, an image is cut out from the added image 136 for upper-layer pattern at a position corresponding to the cut out image 152 to create an image 153 having the same portion as that of the template 69.’ P 78), wherein the overlay shift amount measurement is performed according to results of the matching processes (‘The superposition misalignment amount is calculated, according to the following expressions, from the pixel-based center position 154 (Mx, My) of the upper-layer pattern, pixel-based center position 156 (Nx, Ny) of the lower-layer pattern, and the pixel size S.’ P 79).
Regarding claim 11, Yamamoto et al. in view of Takasugi et al. disclose the overlay shift amount measurement method according to claim 9, wherein the first images are generated based on information of secondary electrons generated by irradiating the sample with the charged particle beams, and the second images are generated based on information of backscattered electrons generated by irradiating the sample with the charged particle beams (‘For example, for the upper-layer pattern, a signal from a secondary electron detector (SE detector) by which an edge portion is clearly imaged is used, while for the lower-layer pattern, a signal from a reflected electron detector (BSE detector) by which material contrast is easily obtained is used.’ P 50).
Regarding claim 12, Yamamoto et al. in view of Takasugi et al. disclose the overlay shift amount measurement method according to claim 9, further comprising: a step of setting the first added number of images and the second added number of images (Takasugi et al., ‘The number of images for forming a single completed image (frame integration number) may be arbitrarily set, and thus a proper value is set in view of conditions such as secondary electron generation efficiency.’ P 49). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the apparatus of Yamamoto et al. to allow for setting of the first and second number of added images as in Takasugi et al. so that the number could be set differently for different imaging conditions.
Regarding claim 13, Yamamoto et al. in view of Takasugi et al. disclose the claimed invention except for determining which specific images are selected for adding from among the plurality of first images and the plurality of second images. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the system and method of Yamamoto et al. to include selection of specific images for adding from among the captured images so that only images taken after the sample has charging effects began to level out, avoiding the large drift amounts that occur in early images, an effect known at least to Takasugi et al. (‘FIG. 11 shows a graph of the drift amount and its approximation curve. When the drift is due to the influence of charging, a tendency is such that the drift amount is large immediately after the start of image acquisition and then gradually converges thereafter.’ P 90).
Regarding claim 15, Yamamoto et al. in view of Takasugi et al. disclose the overlay shift amount measurement method according to claim 9, wherein, in generation of the first added image and the second added image, the first added image and the second added image are generated by adding an after drift correction for reducing an influence due to drift (Takasugi et al., fig. 2, step S2011). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the system of Yamamoto et al. to include the drift correction of Takasugi et al. to reduce blur from drift, a problem with image integration disclosed in Takasugi et al. (‘For example, in the method where the target image is acquired by integrating the image signals obtained by high speed scan on a pixel by pixel basis (frame integration), if there is a drift during image integration due to a charge-up or the like of the sample, pixels with a displaced field of view would be integrated, resulting in the target image after integration being blurred in the drift direction.’ P 2).
Regarding claim 16, Yamamoto et al. in view of Takasugi et al. disclose the claimed invention except for generating a plurality of intermediate images by adding the second images for each third number of images smaller than the second added number of images, and the drift correction is performed according to a shift amount between the plurality of intermediate images. However, it would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the drift correction method of Takasugi et al. in this manner to reduce the computational complexity, as forming intermediate images and performing drift correction in this manner requires looping through the drift correction steps fewer times.
Claims 6 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yamamoto et al. in view of Takasugi et al. as applied to claims 1 & 9 above, and further in view of US 2019/027841 (Xiao).
Regarding claims 6 and 14, Yamamoto et al. in view Takasugi et al. disclose the claimed invention except for generating the added images by adding a plurality of images obtained by differentiating a scanning direction of the charged particle beams. Xiao discloses a charged particle beam system and method for forming added images where the images are obtained by differentiating the scanning direction of the charged particle beams (fig. 3C, steps 354, 356, and 358). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the system and method of Yamamoto et al. to include the multi-directional scanning of Xiao to remove the effect of asymmetries, as disclosed in Xiao (‘In sum, e-beam patterns that scan in both +X and −X (east and west) directions or in both +Y and −Y (north and south) directions can be used to form combined symmetric target images for X and Y direction grating structures, respectively. The asymmetries in the two different images that were formed by the two directional, but symmetrical, scans may then be combined to form a symmetric image. The symmetric image may then be analyzed for accurate overlay (or other measurements, such as CD) determination.’ P 43).
Response to Arguments
Applicant's arguments filed September 2nd, 2025 have been fully considered but they are not persuasive.
Applicant argues that the prior art is silent as to whether the first added number of images is 2 and the second number is 256.
While examiner agrees the arts are silent as to these particular numbers, applicant has shown or even suggested that these particular numbers are critical or solve any particular problem. The arts disclose adding together an arbitrary number of images, and setting the number to any particular value is not inventive unless applicant can show that that particular value is critical or produces some unexpected result.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ELIZA W OSENBAUGH-STEWART/Primary Examiner, Art Unit 2881