DETAILED ACTION
Response to Arguments
Applicant’s arguments, see pages 6-17, filed 11/26/2025, with respect to the rejections based on McGeoch ‘241 have been fully considered and are persuasive. The rejection of the claims based on McGeoch ‘241 has been withdrawn.
Applicant's arguments filed 11/26/2025 with regards to McGeoch ‘028 (WO. 2017/143028) have been fully considered but they are not persuasive. As claims 1-18 have been cancelled and new claims 19-37 have been introduced, Examiner will respond solely on how the art is applied to the pending claims.
Applicant argues that ‘028 does not teach or disclose the creating a 3D magnetic null at the ion generation point such that substantially all ionized debris is channeled along field lines aligned with the null’s fan plane or spine. Applicant relies on arguing that the art of record uses magnetic confinement or partial deflection, which allows significant ion impingement. In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., ion impingement) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). The claimed limitations merely state that ionized debris created at the site is channeled along magnetic field lines that are aligned with either a fan plane or a spine line of each magnetic null, to direct debris away. Fig. 5 of McGeoch ‘028 teaches the magnetic cups field guides the plasma from the interaction region 60 towards the plasma beam dumps 140 arranged azimuthally (e.g. spine line of the magnetic null) around chamber 70, see page 8-9, lines 31-6. Here, the unused or unwanted plasma that is not present at the interaction region 60 is considered debris.
Applicant further argues that ‘028 does not teach the magnetic nulls are generated by a plurality of electromagnetic coils or permanent magnets. Examiner disagrees as Applicant admits that ‘028 introduces multiple current-carrying coils (e.g. coils 10, 20, 30, 40 in Fig. 5, see Page 10 of remarks). Applicant relies upon the inflexibility of arrangements to tune and create different null structures as desired. In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e. adjustable or reconfigurable coil arrangements) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Fig. 5 of ‘028 simply depicts a configuration of coils to create a magnetic null.
Applicant further argues that ‘028 does not teach the plural field generating coils or magnets do not intrude into an EUV light path of the system. Examiner disagrees as Fig. 5 of ‘028 teaches a plurality of coils 30 and 40 are positioned outside a collection optic 110 such that the ray 120 is collected and redirected toward the chamber exit port, unobstructed by the coils. The broadest reasonable interpretation of the claim limitations only requires that none of the magnetic field sources obstruct an EUV light path of the system. As seen in Fig. 5, the ray 120 is unobstructed from generation to being redirected by from the collection optics to the chamber exit port.
Applicant further argues that ‘028 does not teach an additional coil to funnel debris. Examiner disagrees as ‘028 specifically teaches the additional coils 10 and 20 are positioned on or near a spine of the magnetic null, specifically for the purpose of forming the magnetic field depicted by field lines 50 such that the shape is designed to channel a radial plasma flow into an annular plasma beam dump, see page 7, lines 6-19, as claimed.
Applicant further argues that ‘028 does not teach the debris is channeled through a hole in the optics. Examiner disagrees as Fig. 6 clearly depicts an aperture where the spine of the magnetic null directs the plasma from the interaction zone 60 to the annular beam dumps 140 which pass through a gap in the collection optics system 150 and 160.
Applicant further argues that ‘028 does not teach tuning the debris mitigation field configuration. In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., a controlled power supply) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). The broadest reasonable interpretation of the claim language only requires the adjusting the electric current to the at least one of the electromagnetic coils to modify a structure of the magnetic null. ‘028 teaches that a variation of the positions of the coils, geometry of the yoke, and the currents applied allow an infinite variety of field designs (see page 13, lines 7-15).
Applicant argues that ‘028 does not teach the magnetic null is where the droplet is created. Examiner disagrees as Fig. 4 describes how the droplet is delivered toward interaction location 60, where a laser beam 75 passes through a gap between collection optic system 110 and converts the droplet to a plasma and subsequently emits EUV light (see page 8, lines 2-8). Fig. 10 of ‘028 further teaches the magnetic null is formed around the interaction zone 60 (see page 11, lines 1-2), spatially spaced from the collection optics 110.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 22 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 22 recites the limitation "the smaller coil or magnet" in the second line of the claim. There is insufficient antecedent basis for this limitation in the claim. In this action, it will be assumed to be electromagnetic coil that is positioned on or near a spine of the magnetic null.
Claim Rejections - 35 USC § 102
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 person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 27-32, 34, and 36-37 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by McGeoch (WO 2017/143028, hereinafter McGeoch).
Regarding claim 27, McGeoch discloses an LPP EUV apparatus (relates to the production of EUV light, specifically it describes configures of the LPP light source type, see page 1, lines 7-11), comprising:
a collector mirror having a reflective surface for EUV light and defining a central aperture (Fig. 4 shows a gap between the collective optics system 110 where the laser beam 75 enters);
a target delivery mechanism configured to introduce a target material at a plasma generation location spaced apart from the collector mirror (droplet source 85 delivers a stream of material in droplets toward interaction location 60 to be exposed to a laser beam 75 for formation of EUV light, see page 8, lines 2-8; laser beams causes the droplet to form a plasma ball which emits EUV light, see page 8, lines 20-23; spaced apart from the collection optics system 110, see Fig. 4);
a laser excitation source configured to direct a laser beam through the central aperture of the collector mirror to the target material at the plasma generation location, thereby producing a plasma that emits EUV radiation (droplet source 85 delivers a stream of material in droplets toward interaction location 60 to be exposed to a laser beam 75 for formation of EUV light, see page 8, lines 2-8; laser beams causes the droplet to form a plasma ball which emits EUV light, see page 8, lines 20-23; spaced apart from the collection optics system 110, see Fig. 4); and
a plurality of magnetic field generators, each comprising an electromagnetic coil or a permanent magnet, arranged around the plasma generation location and configured to collectively produce a 3D magnetic null field at the plasma generation location, the magnetic null field defining a fan plane and a spine line (cusp magnetic fields are generated by a combination of permanent magnets or current carrying coils, see page 12, lines 25-30; magnetic null formed around the interaction region 60, see Fig. 10 and page 11, lines 1-2; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris) along the spine line (depicted by the arrow lines horizontal from the interaction region 60 towards the beam dumps 140), see Fig. 5 and pages 8-9, lines 31-6).
Regarding claim 28, McGeoch discloses the plurality of magnetic field generators are electromagnetic coils (cusp magnetic fields are generated by a combination of permanent magnets or current carrying coils, see page 12, lines 25-30; used to form the magnetic null, depicted by Fig. 13B, see page 13, lines 7-15).
Regarding claim 29, McGeoch discloses the plurality of magnetic field generators are positioned entirely outside a light cone of EUV radiation collected by the collector mirror, whereby the magnetic field generators lie outside the direct line of sight between the plasma generation location and the collector mirror (plurality of coils 30 and 40 are positioned outside a collection optic 110, such that the EUV light emitted from region 50 to the collection optic 110 is unobstructed by the coils 30 and 40, see Fig. 5 and page 8, lines 12-16).
Regarding claim 30, McGeoch discloses the magnetic field generators are arranged such that the spine line of the magnetic null field is aligned with the central aperture of the collector mirror, thereby providing a path for ionized debris to travel along the spine and exit through the aperture (coil 10 and 20 are positioned near a spine (e.g. the horizontal field lines from interaction region 60 towards the annular beam dump 140) of the magnetic null, facing a collection optic 110 (e.g. sensitive component), see Fig. 5 and page 7, lines 6-19; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
Regarding claim 31, McGeoch discloses a power supply system coupled to the electromagnetic coils and configured to vary currents in the coils to adjust at least one of (i) a position of the magnetic null in 3D space and (ii) a shape of the magnetic null’s fan plane or spine line (size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null, see page 13, lines 11-15; power supply system inherent).
Regarding claim 32, while McGeoch does not explicitly disclose the plurality of magnetic field generators is configured to create a magnetic null with a substantially planar fan plane, McGeoch teaches that size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null (see page 13, lines 11-15). It would have been obvious to the ordinary artisan before the effective filing date to modify the shape of the coil (e.g. to be smaller) to form a desired field shape with reasonable success.
Regarding claim 34, while McGeoch does not explicitly disclose the plurality of magnetic field generators is configured to create a magnetic null with a non-planar fan plane, McGeoch teaches that size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null (see page 13, lines 11-15). It would have been obvious to the ordinary artisan before the effective filing date to modify the shape of the coil (e.g. to be smaller) to form a desired field shape with reasonable success.
Regarding claim 36, McGeoch discloses a power supply configured to vary current through the plurality of magnetic field generators to control a spatial location of the 3D magnetic null (size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null, see page 13, lines 11-15; power supply system is inherent).
Regarding claim 37, McGeoch discloses at least one processor configured to control the power supply (size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null, see page 13, lines 11-15; processor for the power supply system is inherent).
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 19-25, 33, and 35 are rejected under 35 U.S.C. 103 as being unpatentable over McGeoch.
Regarding claim 19, McGeoch discloses a method for mitigating debris and reducing the need for buffer gas in a LPP EUV system (EUV for lithography, specifically configurations if the LPP light source type, see page 1, lines 7-11; including magnetic fields for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see pages 8-9, lines 31-6), comprising:
generating, at a plasma formation site, one or more magnetic nulls defined by one or more 3D magnetic null fields (droplets from droplet source 85 are directed toward interaction location 60 to be exposed to a laser beam 75 for formation of EUV light, see page 8, lines 2-8; laser beams causes the droplet to form a plasma ball which emits EUV light, see page 8, lines 20-23; magnetic null formed around the interaction region 60, see Fig. 10 and page 11, lines 1-2), the one or more 3D magnetic null fields configured such that substantially all ionized debris created by the site is channeled along magnetic field lines that are aligned with either a fan plane or a spine line of each magnetic null, thereby directing the debris away from sensitive components of the EUV system (magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris) along the spine line (depicted by the arrow lines horizontal from the interaction region 60 towards the beam dumps 140), see Fig. 5 and pages 8-9, lines 31-6).
While McGeoch does not explicitly disclose the magnetic null reduces the need for buffer gas, McGeoch teaches the field lines that form the magnetic null are used to direct unwanted plasma away from the interaction region 60 towards the beam dumps 140 (see pages 8-9, lines 31-6). A person of ordinary skill in the art would recognize that an absence of using the magnetic field to guide plasma to a desired location would need another mode of guidance, such as a background or buffer gas, and that the presence of such teaching would be obvious to reduce the need for a guiding gas to direct the debris to a desired location.
Regarding claim 20, McGeoch discloses the one or more 3D magnetic null fields are generated by a plurality of magnetic field sources configured in combination, each source being an electromagnetic coil or a permanent magnet (cusp magnetic fields are generated by a combination of permanent magnets or current carrying coils, see page 12, lines 25-30; used to form the magnetic null, depicted by Fig. 13B, see page 13, lines 7-15).
Regarding claim 21, McGeoch discloses the plurality of magnetic field sources are disposed outside of a collection optical cone of the EUV system, so that none of the sources obstruct an EUV light path of the system (plurality of coils 30 and 40 are positioned outside a collection optic 110, such that the EUV light emitted from region 50 is reflected by collection optic 110 to propagate as typical ray 120 toward the chamber exit port unobstructed by the coils 30 and 40, see Fig. 5 and page 8, lines 12-16).
Regarding claim 22, McGeoch discloses an electromagnetic coil is position on or near a spine of the magnetic null, on a side of the null facing a sensitive component, the coil or magnet being configured to shape the magnetic field and enhance debris removal away from the sensitive component (coil 10 and 20 are positioned near a spine (e.g. the horizontal field lines from interaction region 60 towards the annular beam dump 140) of the magnetic null, facing a collection optic 110 (e.g. sensitive component), see Fig. 5 and page 7, lines 6-19; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
While the coils 10 and 20 are depicted (exemplified in Fig. 1) to be smaller (e.g. thinner) than the other coils, McGeoch teaches that size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null (see page 13, lines 11-15). It would have been obvious to the ordinary artisan before the effective filing date to modify the shape of the coil (e.g. to be smaller) to form a desired field shape with reasonable success.
Regarding claim 23, McGeoch discloses the one or more 3D magnetic null fields are arranged such that a spine of a magnetic null interests a collection mirror of the EUV system, and wherein ionized debris travels along the spine and is channeled through an aperture in the collection mirror (a spine (e.g. the horizontal field lines from interaction region 60 towards the annular beam dump 140) of the magnetic null is positioned in the gap between collection optics system 110 and 160, see Fig. 6; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6; the magnetic field lines guide the plasma through the gap of the collection optics system 110 and 160, see Fig. 6).
Regarding claim 24, McGeoch discloses adjusting an electric current through at least one of the electromagnetic coils to modify a structure or spatial location of the 3D magnetic null, thereby turning the debris mitigation field (the size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null, see page 13, lines 11-15; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
While McGeoch does not explicitly disclose tuning the debris mitigation field for optimal performance, it has been held that discovery of optimum value of result effective variable in known process is ordinarily within skill of art (see In re Boesch, 205 USPQ 215 (CCPA) and In re Aller, 105 USPQ 233 (CCPA 1955) (selection of optimum ranges within prior art general conditions is obvious)).
Regarding claim 25, McGeoch discloses the one or more magnetic null fields are configured such that the ions do not become magnetically trapped within the EUV system but instead eventually exit the magnetic field region (magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
While McGeoch does not explicitly disclose producing unstable ion trajectories, a person of ordinary skill in the art would recognize that a magnetic null is defined as a location where there is no influence from a magnetic field. Therefore, any ions within the magnetic null would be free to traverse the null with a trajectory that is not controlled until it is captured by the magnetic cusp that leads to the beam dump 140 (see pages 8-9, lines 31-6).
Regarding claim 33, McGeoch discloses the plurality of magnetic field generators include at least one additional coil that modifies the magnetic field to guide debris along the spine line (coil 10 and 20 are positioned near a spine (e.g. the horizontal field lines from interaction region 60 towards the annular beam dump 140) of the magnetic null, facing a collection optic 110 (e.g. sensitive component), see Fig. 5 and page 7, lines 6-19; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
While McGeoch does not explicitly disclose the plurality of magnetic field generators is configured to create a magnetic null with a substantially planar fan plane, McGeoch teaches that size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null (see page 13, lines 11-15). It would have been obvious to the ordinary artisan before the effective filing date to modify the shape of the coil (e.g. to be smaller) to form a desired field shape with reasonable success.
Regarding claim 35, McGeoch discloses the plurality of magnetic field generators includes two magnetic field generators, and an additional magnetic field generator, the additional magnetic field generator being centered on a spine on a side of the 3D magnetic null where magnetic fields intersect sensitive components (coil 10 and 20 are positioned near a spine (e.g. the horizontal field lines from interaction region 60 towards the annular beam dump 140) of the magnetic null, facing a collection optic 110 (e.g. sensitive component), see Fig. 5 and page 7, lines 6-19; magnetic field lines that create the null zone around interaction region 60 is used for guiding the plasma from the interaction region 60 towards the plasma beam dumps 140 (e.g. unwanted plasma not centered in the interaction region 60 is considered debris), see Fig. 5 and pages 8-9, lines 31-6).
While McGeoch does not explicitly disclose the generators have a specified diameter, McGeoch teaches that size, shape, and strength of the coils can all be varied to design a desired cusp field to form the magnetic null (see page 13, lines 11-15). It would have been obvious to the ordinary artisan before the effective filing date to modify the shape of the coil (e.g. to be smaller) to form a desired field shape with reasonable success.
Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over McGeoch in view of Nagai et al. (US Pat. 7,999,241, hereinafter Nagai).
Regarding claim 26, McGeoch fails to explicitly disclose the debris mitigation is performed without relying on a buffer gas to slow or stop the ions such that the EUV system operates at vacuum or a minimal background gas pressure insufficient to substantially collisionally thermalize the ions.
Nagai teaches debris generated inside a magnetic field converges in a direction of the magnetic field by the magnetic field (see col. 2, lines 25-36) without the use of a gas. Nagai discloses that by directing the debris with a magnetic field is advantageous for reducing contamination and damage to nearby optical elements (see col. 2, lines 25-36).
Nagai modifies McGeoch by suggesting debris mitigation by use of a magnetic field without the use of a buffer gas.
Since both inventions are drawn to plasma EUV debris mitigation (and Nagai is incorporated in full in McGeoch, see page 2, lines 3-6 (Nagai is designated as reference #18, see page 15)) it would have been obvious to the ordinary artisan before the effective filing date to modify McGeoch by having the debris mitigation by use of a magnetic field without the use of a buffer gas for the purpose of reducing contamination and damage to nearby optical elements as taught by Nagai.
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.
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/HC/Examiner, Art Unit 2878
/GEORGIA Y EPPS/Supervisory Patent Examiner, Art Unit 2878