Prosecution Insights
Last updated: April 19, 2026
Application No. 18/138,709

HEIGHT SENSING SYSTEM FOR ELECTRON BEAM METROLOGY TOOL

Non-Final OA §103
Filed
Apr 24, 2023
Examiner
TSAI, HSIEN C
Art Unit
2881
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Kla Corporation
OA Round
1 (Non-Final)
84%
Grant Probability
Favorable
1-2
OA Rounds
2y 4m
To Grant
98%
With Interview

Examiner Intelligence

Grants 84% — above average
84%
Career Allow Rate
264 granted / 315 resolved
+15.8% vs TC avg
Moderate +14% lift
Without
With
+14.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
21 currently pending
Career history
336
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
62.0%
+22.0% vs TC avg
§102
27.2%
-12.8% vs TC avg
§112
6.7%
-33.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 315 resolved cases

Office Action

§103
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 . 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) 1-19 are rejected under 35 U.S.C. 103 as being unpatentable over Gunji (US 2009/0309022) in view of Kim (US 5,742,397). Regarding claim 1, Gunji teaches a system (Fig. 10) comprising a stage (1117) configured to hold a workpiece (1108), an electron beam column (1101/1010) configured to direct an electron beam at the workpiece (1108) on the stage (1117); a light source (1125) configured to generate a light beam at the workpiece (1108) on the stage; a sensor (1030) configured to receive the light beam reflected from the workpiece (¶ 0116); and a processor (computer 1123) in electronic communication with the sensor, wherein the processor is configured to use measurements from the sensor to determine a displacement from a nominal distance (height; ¶ 0113) between the electron beam column and the workpiece on the stage (using height detecting system 1050; ¶ 0118). Gunji fails to further teach a mirror configured to reflect the light beam received from the workpiece toward the sensor. Kim teaches a control device (Fig. 3) for positioning a target (300) on a stage (200), wherein mirrors (4 and 5) are using in an optical section to control the light-paths in order to adjust the position of the target and allow detection (Col. 4 lines 29-46). It would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate mirrors configured to reflect the light beam received from the workpiece toward the sensor in Gunji’s system, in order to control the light-paths, adjust the position of the target and allow detection. Regarding claim 2, Gunji in view of Kim teaches the system of claim 1, further comprising a second mirror (5), wherein the second mirror (Kim Fig. 3) is positioned in a path of the light beam, wherein one of the mirrors (mirror 4) is positioned to direct the light beam from the light source at the workpiece, and wherein one of the mirrors (mirror 5) is positioned to direct the light beam from the workpiece at the mirror. Gunji in view of Kim fails to further teach a third mirror. However it would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate additional mirror in the light-path, since it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art. St. Regis Paper Co. v. Bemis Co., 193 USPQ 8. Regarding claim 3, Gunji in view of Kim teaches the system of claim 2, further comprising plano-convex lenses disposed in the path of the light beam between the second mirror and the workpiece. Regarding claim 4, Gunji in view of Kim teaches the system of claim 2, but fails to further teach that the second mirror and the third mirror are each a fold mirror. However, it would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate a fold mirror in Gunji and Kim’s devices because fold mirrors are known and used in exposure devices to reflect light from both sides (see evidentiary reference: Goodwin US 2017/0097574). Regarding claim 5, Gunji in view of Kim teaches the system of claim 1, further comprising a beam splitter (Kim 22) positioned in a path of the light beam between the workpiece and the light source, wherein the beam splitter directs at least some of the light beam at the sensor (Kim Fig. 3). Regarding claim 6, Gunji in view of Kim teaches the system of claim 1, wherein the light source is a light-emitting diode (Kim Col. 6 lines 17-18). Regarding claim 7, Gunji in view of Kim teaches the system of claim 1, but fails to further teach a convex lens in a path of the light beam between the light source and the workpiece. However, it would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate a convex lens, because a convex lens is well known and used in the exposure art. Regarding claim 8, Gunji in view of Kim teaches the system of claim 1, further comprising a slit in a path of the light beam between the light source and the workpiece (¶ 0133-0134). Regarding claim 9, Gunji in view of Kim teaches the system of claim 1, but fails to further teach that the mirror is a spherical mirror. However, it would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate a spherical mirror, because a convex lens is well known and used in the exposure art. Regarding claim 10, Gunji in view of Kim teaches the system of claim 1, wherein the workpiece is a semiconductor wafer (Gunji ¶ 0001). Regarding claim 11, Gunji teaches a method comprising; directing a beam of light (Fig. 10) from a light source (1125) at a workpiece (1108) on a stage (1117), wherein the workpiece (1108) is disposed an absolute distance from an electron beam column (1101/1010); receiving the beam of light coming off the workpiece (1108) at a sensor (1030); and determine, using a processor (computer 1123), a displacement from a nominal distance between the electron beam column and the workpiece on the stage (using height detecting system 1050; ¶ 0118). Gunji fails to explicitly teach a step of reflecting the beam of light off the workpiece. Kim teaches a control device (Fig. 3) for positioning a target (300) on a stage (200), wherein reflecting mirrors (4 and 5) are using in an optical section to control the light-paths in order to adjust the position of the target and allow detection (Col. 4 lines 29-46). It would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate a step of using mirrors to reflect the light beam received from the workpiece toward the sensor in Gunji’s system, in order to control the light-paths, adjust the position of the target and allow detection. Regarding claim 12, Gunji in view of Kim teaches the system of claim 11, wherein the workpiece is a semiconductor wafer (Gunji ¶ 0001). Regarding claim 13, Gunji in view of Kim teaches the system of claim 11, further comprising reflecting the beam of light reflected off the workpiece using a mirror (Kim 4 or 5), and wherein the reflecting the beam of light off the workpiece directs the beam of light to the mirror (Kim Fig. 3). Regarding claim 14, Gunji in view of Kim teaches the system of claim 13, wherein the directing includes reflecting the beam of light off a second mirror (4 or 5) disposed in a path of the beam of light between the light source and the workpiece. Regarding claim 15, Gunji in view of Kim teaches the system of claim 14, but fails to further teach that the reflecting the beam of light off the workpiece includes reflecting the beam of light off a third mirror disposed in the path of the beam of light between the workpiece and the mirror. However, it would have been obvious to one of ordinary skill in the art at the time of the effective filing of the claimed invention to incorporate additional mirrors in the light-path, since it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art. St. Regis Paper Co. v. Bemis Co., 193 USPQ 8. Regarding claim 16, Gunji in view of Kim teaches the system of claim 11, further comprising splitting the beam of light reflected off the workpiece using a beam splitter (Kim 22), wherein some of the beam of light is directed by the beam splitter to the sensor (Kim Fig. 3). Regarding claim 17, Gunji in view of Kim teaches the system of claim 11, wherein the directing further includes focusing the beam of light (using focusing section 1138; ¶ 0119). Regarding claim 18, Gunji in view of Kim teaches the system of claim 11, further comprising directing the beam of light reflected off the workpiece at a same point on the workpiece a second time before the beam of light is received at the sensor (operation repeated; ¶ 0147). Regarding claim 19, Gunji in view of Kim teaches the system of claim 11, further comprising adjusting a height of a stage based on the displacement from the nominal distance (using height detecting system 1050; ¶ 0118). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to HSIEN C TSAI whose telephone number is (571)272-7438. The examiner can normally be reached Monday-Tuesday (8-5). Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Robert Kim can be reached at 571-272-2293. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /HSIEN C TSAI/Examiner, Art Unit 2881 /WYATT A STOFFA/Primary Examiner, Art Unit 2881
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Prosecution Timeline

Apr 24, 2023
Application Filed
Dec 28, 2025
Non-Final Rejection — §103 (current)

Precedent Cases

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DETECTOR
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SCINTILLATOR AND CHARGED PARTICLE RADIATION APPARATUS
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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
84%
Grant Probability
98%
With Interview (+14.3%)
2y 4m
Median Time to Grant
Low
PTA Risk
Based on 315 resolved cases by this examiner. Grant probability derived from career allow rate.

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