Office Action Predictor
Last updated: April 15, 2026
Application No. 18/528,933

APPARATUS FOR AND METHOD OF REDUCING CONTAMINATION FROM SOURCE MATERIAL IN AN EUV LIGHT SOURCE

Final Rejection §103
Filed
Dec 05, 2023
Examiner
CHANG, HANWAY
Art Unit
2878
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Asml Netherlands B.V.
OA Round
4 (Final)
86%
Grant Probability
Favorable
5-6
OA Rounds
2y 1m
To Grant
89%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
538 granted / 626 resolved
+17.9% vs TC avg
Minimal +3% lift
Without
With
+2.9%
Interview Lift
resolved cases with interview
Fast prosecutor
2y 1m
Avg Prosecution
65 currently pending
Career history
691
Total Applications
across all art units

Statute-Specific Performance

§101
1.5%
-38.5% vs TC avg
§103
38.4%
-1.6% vs TC avg
§102
34.8%
-5.2% vs TC avg
§112
6.0%
-34.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 626 resolved cases

Office Action

§103
DETAILED ACTION Response to Arguments Applicant’s arguments with respect to the claims have been considered but are moot because the remarks do not apply to the current grounds of rejection, the previous grounds being changed out of necessity by applicant's amendment. 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. Claims 1-3, 5-10, 12-17 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Bruls et al. (WO 2015/055374, hereinafter Bruls) in view of Su et al. (US PGPub 2020/0008290, hereinafter Su). Regarding claim 1, Bruls discloses an apparatus for generating EUV radiation (radiation source using a plasma to generate EUV radiation for a lithographic apparatus, see paragraph [0002]), the apparatus comprising: a vessel (an enclosing structure 4220, see paragraph [0058]); a collector mirror positioned within the vessel (radiation collector CO which may be a grazing incidence collector, see paragraph [0060]), wherein the collector mirror has a first focal point within the vessel where target material may be irradiated to produce plasma and a second focal point (EUV radiation emitting plasma 4210 is formed by a discharged produced plasma source, see paragraph [0058]; near a focal point of the radiation collector CO, see Fig. 4; second focal point being the virtual source point IF, see paragraph [0060]), the first focal point being located between the collector mirror and the second focal point (EUV radiation emitting plasma 4210 is between the radiation collector CO and the virtual source point IF); an exhaust port positioned in a side wall of the vessel to remove gas from the vessel prior to the oxygen gas reaching the first focal point (gas outlet 112 provided in the exit cone 95, see Fig. 20 and paragraph [00103]; used to flow gas out of the vessel through gas flow 113 before reaching the EUV radiation emitting plasma 4210, see Fig. 21); and at least one inlet in fluid communication with a gas source (e.g. a flow of buffer gas, such as hydrogen or an inert gas) and positioned in the side wall in a region between the exhaust port and the second focal point (gas outlet 111 located between the gas outlet 112 and virtual source point IF, see Fig. 20; gas outlet provides gas flow 113 from gas outlet 111 to gas outlet 112, see Fig. 20 and paragraph [00103]). Bruls fails to disclose the source of oxygen gas. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 2, Bruls fails to disclose the oxygen gas comprises molecular oxygen. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 3, Bruls fails to disclose the radicals are oxygen radicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 5, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Regarding claim 6, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Regarding claim 7, Bruls discloses a partial pressure of the gas in the range of about 10E-2 (partial pressure of 10 Pa, equivalent to 10E-2 mbar, see paragraph [0058]). Regarding claim 8, Bruls discloses an apparatus for generating EUV radiation (radiation source using a plasma to generate EUV radiation for a lithographic apparatus, see paragraph [0002]), the apparatus comprising: a vessel (an enclosing structure 4220, see paragraph [0058]); a collector mirror positioned within the vessel (radiation collector CO which may be a grazing incidence collector, see paragraph [0060]), the collector mirror having a primary focus (EUV radiation emitting plasma 4210 is formed by a discharged produced plasma source, see paragraph [0058]; near a focal point of the radiation collector CO, see Fig. 4); at least one exhaust port positioned in a side wall of the vessel to remove gas from the vessel prior to the oxygen gas reaching the first focal point (gas outlet 112 provided in the exit cone 95, see Fig. 20 and paragraph [00103]; used to flow gas out of the vessel through gas flow 113 before reaching the EUV radiation emitting plasma 4210, see Fig. 21); and at least one inlet adapted to be placed in fluid communication with a gas source (e.g. a flow of buffer gas, such as hydrogen or an inert gas) and positioned in the side wall in a region between the exhaust port and the second focal point (gas outlet 111 located between the gas outlet 112 and virtual source point IF, see Fig. 20; gas outlet provides gas flow 113 from gas outlet 111 to gas outlet 112, see Fig. 20 and paragraph [00103]). Bruls fails to disclose the source of oxygen gas. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 9, Bruls fails to disclose the oxygen gas comprises molecular oxygen. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 10, Bruls fails to disclose the radicals are oxygen radicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 12, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Regarding claim 13, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Regarding claim 14, Bruls discloses a partial pressure of the gas in the range of about 10E-2 (partial pressure of 10 Pa, equivalent to 10E-2 mbar, see paragraph [0058]). Regarding claim 15, Bruls discloses an apparatus for generating EUV radiation (radiation source using a plasma to generate EUV radiation for a lithographic apparatus, see paragraph [0002]), the apparatus comprising: a vessel (an enclosing structure 4220, see paragraph [0058]); a collector mirror positioned within the vessel (radiation collector CO which may be a grazing incidence collector, see paragraph [0060]), wherein the collector mirror has a first focal point within the vessel where target material may be irradiated to produce plasma and a second focal point (EUV radiation emitting plasma 4210 is formed by a discharged produced plasma source, see paragraph [0058]; near a focal point of the radiation collector CO, see Fig. 4; second focal point being the virtual source point IF, see paragraph [0060]), the first focal point being located between the collector mirror and the second focal point (EUV radiation emitting plasma 4210 is between the radiation collector CO and the virtual source point IF); an exhaust port positioned in a side wall of the vessel (gas outlet 112 provided in the exit cone 95, see Fig. 20 and paragraph [00103]); and at least one inlet in fluid communication with a gas source (e.g. a flow of buffer gas, such as hydrogen or an inert gas) and positioned in the side wall in a region between the exhaust port and the second focal point (gas outlet 111 located between the gas outlet 112 and virtual source point IF, see Fig. 20; gas outlet provides gas flow 113 from gas outlet 111 to gas outlet 112, see Fig. 20 and paragraph [00103]). Bruls fails to disclose the source of oxygen gas. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 16, Bruls fails to disclose the oxygen gas comprises molecular oxygen. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 17, Bruls fails to disclose the radicals are oxygen radicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]). Su modifies Bruls by providing a gas source to be oxygen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to be oxygen at the gas outlet 111 for the purpose of removing excess tin through etching as taught by Su. Regarding claim 19, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Regarding claim 20, Bruls fails to disclose the source of oxygen gas further comprises one or more of the listed chemicals. Su discloses providing a gas to generate radicals/ions for removing excess tin by etching (see paragraph [0038]; flowing from gas inlet 21 to gas outlet 22, see Fig. 4 and paragraph [0042]), wherein the gas can be oxygen (see paragraph [0039]) or a halogen (in some embodiments, a halogen containing gas is utilized, see paragraph [0038]). Su modifies Bruls by providing a gas source to include a halogen. Since both inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify Bruls by providing a gas source to include a halogen at the gas outlet 111 for free radicals for the purpose of removing excess tin through etching as taught by Su. Claims 4, 11, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Bruls in view of Su and in further view of De Dea et al. (US Pat. 10,232,413, hereinafter De Dea). Regarding claim 4, the combination of Bruls and Su fails to disclose the source of oxygen gas further comprises a source of methane. De Dea teaches providing a gas capable of being dissociated into free radials for cleaning (see col. 6, lines 45-56). De Dea further teaches the gas composition for providing free radicals can include hydrogen, methane, or water, in addition to oxygen (see col. 19, lines 46-58). De Dea modifies the combination of Bruls and Su by providing a gas source to include methane. Since all inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify the combination of Bruls and Su by providing a gas source of free radicals to include methane for the purpose of being dissociated into free radials for cleaning as taught by De Dea. Regarding claim 11, the combination of Bruls and Su fails to disclose the source of oxygen gas further comprises a source of methane. De Dea teaches providing a gas capable of being dissociated into free radials for cleaning (see col. 6, lines 45-56). De Dea further teaches the gas composition for providing free radicals can include hydrogen, methane, or water, in addition to oxygen (see col. 19, lines 46-58). De Dea modifies the combination of Bruls and Su by providing a gas source to include methane. Since all inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify the combination of Bruls and Su by providing a gas source of free radicals to include methane for the purpose of being dissociated into free radials for cleaning as taught by De Dea. Regarding claim 18, the combination of Bruls and Su fails to disclose the source of oxygen gas further comprises a source of methane. De Dea teaches providing a gas capable of being dissociated into free radials for cleaning (see col. 6, lines 45-56). De Dea further teaches the gas composition for providing free radicals can include hydrogen, methane, or water, in addition to oxygen (see col. 19, lines 46-58). De Dea modifies the combination of Bruls and Su by providing a gas source to include methane. Since all inventions are drawn to plasma EUV radiation sources, it would have been obvious to the ordinary artisan before the effective filing date to modify the combination of Bruls and Su by providing a gas source of free radicals to include methane for the purpose of being dissociated into free radials for cleaning as taught by De Dea. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to HANWAY CHANG whose telephone number is (571)270-5766. The examiner can normally be reached Monday - Friday 7:30 AM - 4:00 PM EST. 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, Georgia Epps can be reached at (571) 272-2328. 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. /HC/ Examiner, Art Unit 2878 /GEORGIA Y EPPS/ Supervisory Patent Examiner, Art Unit 2878
Read full office action

Prosecution Timeline

Dec 05, 2023
Application Filed
Jan 17, 2025
Non-Final Rejection — §103
Apr 15, 2025
Response Filed
May 05, 2025
Non-Final Rejection — §103
Jul 23, 2025
Response Filed
Sep 09, 2025
Non-Final Rejection — §103
Nov 25, 2025
Response Filed
Feb 06, 2026
Final Rejection — §103
Apr 08, 2026
Response after Non-Final Action

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
86%
Grant Probability
89%
With Interview (+2.9%)
2y 1m
Median Time to Grant
High
PTA Risk
Based on 626 resolved cases by this examiner. Grant probability derived from career allow rate.

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