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 .
Specification
The disclosure is objected to because of informalities indicated in an attached, marked-up copy of the specification showing tracking of changes.
Appropriate correction is required.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they do not include the following reference sign(s) mentioned in the description: r. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
In addition to Replacement Sheets containing the corrected drawing figure(s), applicant is required to submit a marked-up copy of each Replacement Sheet including annotations indicating the changes made to the previous version. The marked-up copy must be clearly labeled as “Annotated Sheets” and must be presented in the amendment or remarks section that explains the change(s) to the drawings. See 37 CFR 1.121(d)(1). Failure to timely submit the proposed drawing and marked-up copy will result in the abandonment of the application.
Claim Objections
Claims 16-24 and 26-27 are objected to because of informalities indicated in an attached, marked-up copy of the claims showing tracking of changes.
Appropriate correction is required.
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: “a detection system” in claim 1; and “a control system” in claim 24.
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 § 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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or non-obviousness.
Claim(s) 16, 21-22 and 24-30 is/are rejected under 35 U.S.C. 103 as being unpatentable over Moriya et al. (US 2013/0119232 A1) in view of Innes et al. (US 6,219,146 B1).
Regarding independent Claim 16, Moriya discloses a laser beam metrology system configured to co-operate with a laser beam system (Figure 2: element 51 is an EUV light generation control device; [0072]) that is configured to sequentially direct a first laser beam pulse (Figure 2: element 42 is a pre-pulse laser beam; [0064]) and a second laser beam pulse (Figure 2: element 33 is a main pulse laser beam; [0064]) to a target (Figure 2: element 27 is a plurality of targets in the form of droplets; [0066]) along two independent optical paths (Figure 2: pre-pulse laser beam element 42 and main pulse laser beam element 33 have different paths; [0008] “a beam path of a first laser beam and a beam path of a second laser beam”), but does not specifically teach:
a beam steering device configured to:
redirect a portion of a reflection of the first laser beam pulse along a first direction, the reflection being reflected off of the target, and
reflect a portion of the second laser beam pulse along a second direction; and
a detection system configured to:
receive the reflected portion of the second laser beam pulse,
receive the redirected portion of the reflection of the first laser beam pulse, and
determine a relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse.
However, Innes, in the same field of optical alignment, teaches:
a beam steering device (Figure 1: interferometric system element 90 [Column 3, line 67] and beamsplitter element 112 [Column 4, line 8] are interpreted as a beam steering device) configured to:
redirect a portion of a reflection of the first laser beam pulse along a first direction (Figure 1; [Column 4, lines 13-14] “beamsplitter 112, which then partially reflects beam portion 106a along a reflected beam axis 126”), the reflection being reflected off of the target (Figure 1; [Column 4, lines 11-12] “reflective surface 102, which reflects beam portion 106a back along a beam axis 124”), and
reflect a portion of the second laser beam pulse along a second direction (Figure 1; [Column 4, lines 15-16] “reflect a beam portion 106b of laser beam 106 along a beam axis 114”); and
a detection system (Figure 1; [Column 6, lines 2-4] “an optional image detecting device 132 (e.g., video camera or photodetector array, shown shaded in FIG. 1)”) configured to:
receive the reflected portion of the second laser beam pulse (Figure 1; [Column 5, line 63 – Column 6, line 3] “respective point images *a and *b of sample beam portion 106a and reference beam portion 106b, …. In some embodiments, point images *a and *b … are projected through telescope 120 onto an optional image detecting device 132”, wherein point image *b of “reference beam portion 106b” represents the reflected portion of the second laser beam pulse),
receive the redirected portion of the reflection of the first laser beam pulse (Figure 1; [Column 5, line 63 – Column 6, line 3] “respective point images *a and *b of sample beam portion 106a and reference beam portion 106b, …. In some embodiments, point images *a and *b … are projected through telescope 120 onto an optional image detecting device 132”, wherein point image *a of “sample beam portion 106a” represents the redirected portion of the reflection of the first laser beam pulse), and
determine a relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse ([Column 8, lines 16-17] “Apparatus 100 can equally be used to test the counter parallelism of any two essentially parallel light beams”, wherein “two essentially parallel light beams” are interpreted as reflection of the first laser beam pulse and the second laser beam pulse).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Innes, for a beam steering device configured to: redirect a portion of a reflection of the first laser beam pulse along a first direction, the reflection being reflected off of the target, and reflect a portion of the second laser beam pulse along a second direction; and a detection system configured to: receive the reflected portion of the second laser beam pulse, receive the redirected portion of the reflection of the first laser beam pulse, and determine a relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse, because “the apparatus according to the present invention has no moving parts, has no calibrated circle, and does not depend on accurate positioning or orientation of either beamsplitter or retroreflector.” (Innes, Column 8, lines 12-15)
Regarding Claim 21, modified Moriya discloses the laser beam metrology system of claim 16, further comprising a second optical element (Figure 2: element 374 is a polarization beam splitter; [0057]) configured to:
redirect a part of the reflected portion of the second laser beam pulse (Figure 2; [0070] “polarization beam splitter 374 may reflect the backpropagating beam 43 incident thereon”) to the detector system (Figure 2; [0070] “reflected backpropagating beam 43 may enter the optical detector 370”), but does not specifically teach a second optical element configured to:
substantially redirect the redirected portion of the reflection of the first laser beam pulse to the detector system.
However, Moriya, in a different embodiment – see Figure 13 – teaches a second optical element (Figure 13: element 374 is a polarization beam splitter; [0141]) configured to:
substantially redirect the redirected portion of the reflection (Figure 13: element 424 is a backpropagating beam; [0142]) of the first laser beam pulse (Figure 13: element 423 is a guide laser beam; [0139]) to the detector system (Figure 13; [0142] “The backpropagating beam 424 may travel …, and be reflected by the polarization beam splitter 374 to enter the optical detector 370”).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system in Figure 2 of Moriya with the teachings of the embodiment in Figure 13 of Moriya, for a second optical element configured to: substantially redirect the redirected portion of the reflection of the first laser beam pulse to the detector system, because “a target … does not need to be diffused only to adjust the laser beam focusing optical system …, and debris may be prevented from being generated.” (Moriya, para 154)
Regarding Claim 22, modified Moriya discloses the laser beam metrology system of claim 21, wherein the part of the reflected portion of the second laser beam pulse (Figure 2; [0070] “polarization beam splitter 374 may reflect the backpropagating beam 43 incident thereon”), and the redirected portion of the reflection (Figure 13: element 424 is a backpropagating beam; [0142]) of the first laser beam pulse (Figure 13: element 423 is a guide laser beam; [0139]), are redirected in substantially a same direction (Figure 2; [0070] “reflected backpropagating beam 43 may enter the optical detector 370” and Figure 13; [0142] “The backpropagating beam 424 may travel …, and be reflected … to enter the optical detector 370”).
Regarding Claim 24, Moriya discloses a laser beam system comprising:
a first laser beam source (Figure 2: element 40 is a pre-pulse laser apparatus; [0057]) configured to generate a plurality of first laser beam pulses (Figure 2; [0059] “configured to output a pre-pulse laser beam 41”);
a second laser beam source (Figure 2: element 30 is a main pulse laser apparatus; [0057]) configured to generate a plurality of second laser beam pulses (Figure 2; [0058] “main pulse laser beam 31”);
an optical assembly (Figure 2; [0057] “a high-reflection mirror 341, a dichroic mirror 342, …, high-reflection mirrors 401 and 402, a wavefront adjuster 350, a quarter-wave plate 360, …, a polarization beam splitter 374”; [0062] “laser beam focusing optical system 22A” are interpreted as comprising an optical assembly) configured to direct the plurality of first laser beam pulses (Figure 2; [0059] “pre-pulse laser beam 41”) and the plurality of second laser beam pulses (Figure 2; [0058] “main pulse laser beam 31”) to a respective plurality of targets (Figure 2; [0066] “targets 27 in the form of droplets”); and
a control system (Figure 2; [0072] “The EUV light generation controller 5A may include an EUV light generation control device 51, a reference clock generator 52, a target controller 53, a target generation driver 54, and a delay circuit 55. The EUV light generation control device 51 may be connected to the reference clock generator 52, the target controller 53, and an exposure apparatus controller 61”) configured to control the first laser beam source (Figure 2; [0072] “The EUV light generation control device 51 may further be connected to … the pre-pulse laser apparatus 40 through the delay circuit 55”), the second laser beam source (Figure 2; [0072] “The EUV light generation control device 51 may further be connected to the main pulse laser apparatus 30 … through the delay circuit 55”) and the optical assembly (Figure 2; [0094] “the EUV light generation control device 51 may control the laser beam focusing optical system 22A through the driver 75”), to sequentially direct ([0067] “sequentially irradiated”) a first laser beam pulse (Figure 2; [0059] “pre-pulse laser beam 41”) of the plurality of first laser beam pulses (Figure 2; [0067] “pre-pulse laser beam 42”) and a second laser beam pulse (Figure 2; [0058] “main pulse laser beam 31”) of the plurality of second laser beam pulses (Figure 2; [0067] “main pulse laser beam 33”) onto a target (Figure 2; [0067] “A target 27 that has reached the plasma generation region 25 may be sequentially irradiated”) of the plurality of targets (Figure 2; [0066] “targets 27 in the form of droplets”), but does not specifically teach a laser beam metrology system of claim 16.
However, Moriya modified by Innes teaches a laser beam metrology system of claim 16 (see claim 16 rejection).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the laser beam system of Moriya, with a laser beam metrology system of claim 16, as taught by Moriya combined with Innes, because a laser beam metrology system is essential for ensuring industrial lasers and scientific instruments operate precisely and safely without physical contact.
Regarding Claim 25, modified Moriya discloses the laser beam system of claim 24, wherein the optical assembly is configured to:
provide a first optical path for the plurality of first laser beam pulses (Figure 2; [0059] “pre-pulse laser beam 41 may be reflected sequentially by the high-reflection mirrors 401 and 402, and may enter the wavefront adjuster 350 through the polarization beam splitter 374”; [0060] “pre-pulse laser beam 41 that has passed through the wavefront adjuster 350 may be transmitted through the quarter-wave plate 360 and be incident on the dichroic mirror 342”; [0061] “dichroic mirror 342 may be coated on a first surface thereof with a film configured to … transmit the pre-pulse laser beam 41 with high transmittance”; [0063] “pre-pulse laser beam 41 that have entered the chamber 2A through the window 21 may enter the laser beam focusing optical system 22A”; [0064] “pre-pulse laser beam 41 that have entered the laser beam focusing optical system 22A may first be reflected by the laser beam focusing mirror 71 toward the high-reflection mirror 72. The high-reflection mirror 72 may reflect … the pre-pulse laser beam 41 to be focused in the plasma generation region 25 as … a pre-pulse laser beam 42”) between the first laser beam source (Figure 2: element 40 is a pre-pulse laser apparatus; [0057]) and the target (Figure 2; [0067] “A target 27 that has reached the plasma generation region 25”), and
provide a second optical path for the plurality of second laser beam pulses (Figure 2; [0058] “A main pulse laser beam 31 outputted from the main pulse laser apparatus 30 may be reflected sequentially by the high-reflection mirror 341 and the dichroic mirror 342, and may enter the chamber 2A as a main pulse laser beam 32. […] The high-reflection mirror 341 may be coated with a film configured to reflect the main pulse laser beam 31 with high reflectance”; [0061] “dichroic mirror 342 may be coated on a first surface thereof with a film configured to reflect the main pulse laser beam 32 with high reflectance”; [0063] “main pulse laser beam 32 … that have entered the chamber 2A through the window 21 may enter the laser beam focusing optical system 22A”; [0064] “main pulse laser beam 32 … that have entered the laser beam focusing optical system 22A may first be reflected by the laser beam focusing mirror 71 toward the high-reflection mirror 72. The high-reflection mirror 72 may reflect the main pulse laser beam 32 … to be focused in the plasma generation region 25 as a main pulse laser beam 33”) between the second laser beam source (Figure 2: element 30 is a main pulse laser apparatus; [0057]) and the target (Figure 2; [0067] “A target 27 that has reached the plasma generation region 25”).
Regarding Claim 26, modified Moriya discloses the laser beam system according to claim 25, but does not specifically teach that a first optical element of the laser beam metrology system is arranged in the second optical path.
However, Innes, in the same field of optical alignment, teaches that a first optical element (Figure 1: element 112 is a beamsplitter; [Column 4, line 8]) of the laser beam metrology system (see claim 16 rejection) is arranged in the second optical path (Figure 1: beamsplitter element 112 receives laser beam 106 pointing to the right, wherein the path of laser beam 106 is interpreted as the second optical path).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the laser beam system of Moriya with the teachings of Innes, wherein a first optical element of the laser beam metrology system is arranged in the second optical path, because in EUV systems, beam splitters are essential for the drive laser system that generates the EUV plasma, allowing engineers to sample and redirect 1% – 10% of the beam for real-time profiling, energy monitoring, and safety verification without causing significant power loss to the main beam used for tin droplet ignition.
Regarding Claim 27, modified Moriya discloses the laser beam system according to claim 26, wherein the optical assembly (Figure 2; [0057] “a high-reflection mirror 341, a dichroic mirror 342, …, high-reflection mirrors 401 and 402, a wavefront adjuster 350, a quarter-wave plate 360, …, a polarization beam splitter 374”; [0062] “laser beam focusing optical system 22A” are interpreted as comprising an optical assembly) comprises a first guiding element (Figure 2; [0062] “laser beam focusing optical system 22A” is interpreted as first guiding element) arranged in the second optical path (Figure 2; [0058] “A main pulse laser beam 31 outputted from the main pulse laser apparatus 30 may be reflected sequentially by the high-reflection mirror 341 and the dichroic mirror 342, and may enter the chamber 2A as a main pulse laser beam 32. […] The high-reflection mirror 341 may be coated with a film configured to reflect the main pulse laser beam 31 with high reflectance”; [0061] “dichroic mirror 342 may be coated on a first surface thereof with a film configured to reflect the main pulse laser beam 32 with high reflectance”; [0063] “main pulse laser beam 32 … that have entered the chamber 2A through the window 21 may enter the laser beam focusing optical system 22A”; [0064] “main pulse laser beam 32 … that have entered the laser beam focusing optical system 22A may first be reflected by the laser beam focusing mirror 71 toward the high-reflection mirror 72. The high-reflection mirror 72 may reflect the main pulse laser beam 32 … to be focused in the plasma generation region 25 as a main pulse laser beam 33”), the first guiding element (Figure 2; [0062] “laser beam focusing optical system 22A” is interpreted as first guiding element) configured to:
guide the second laser beam pulse along the second optical path (Figure 2; [0064] “main pulse laser beam 32 … that have entered the laser beam focusing optical system 22A may first be reflected by the laser beam focusing mirror 71 toward the high-reflection mirror 72. The high-reflection mirror 72 may reflect the main pulse laser beam 32 … to be focused in the plasma generation region 25 as a main pulse laser beam 33”) towards the target (Figure 2; [0067] “A target 27 that has reached the plasma generation region 25”), and
guide the reflection (Figure 2; [0070] “The backpropagating beam 43 may travel through the laser beam focusing optical system 22A”, wherein “laser beam focusing optical system 22A” guides “backpropagating beam 43”) of the first laser beam pulse (Figure 2; [0070] “A part of the pre-pulse laser beam 42 that has struck the target 27 may be reflected by the target 27 as a backpropagating beam 43”) substantially opposite the second optical path (Figure 2: backpropagating beam 43 is substantially opposite main pulse laser beam 33) towards the first optical element (Figure 2; [0070] “polarization beam splitter 374 may reflect the backpropagating beam 43 incident thereon”, wherein “polarization beam splitter 374” is interpreted as first optical element).
Regarding Claim 28, modified Moriya discloses the laser beam system according to claim 24, wherein a radiation wavelength of the plurality of first laser beam pulses (Figure 2; [0059] “a pre-pulse laser beam 41 at a central wavelength of approximately 1.06 μm”) is different from a radiation wavelength of the plurality of second laser beam pulses (Figure 2; [0091] “the main pulse laser beam 31 and the pre-pulse laser beam 41 are focused at distinct wavelengths”).
Regarding Claim 29, modified Moriya discloses the laser beam system according to claim 28, wherein the radiation wavelength of the plurality of second laser beam pulses is approximately 10 times higher (Figure 2; [0244] “when the main pulse laser beam 33 is a CO2 laser beam”, the wavelength is 10.6 µm, as known in the art) than the radiation wavelength of the plurality of first laser beam pulses (Figure 2; [0059] “a pre-pulse laser beam 41 at a central wavelength of approximately 1.06 μm”).
Regarding Claim 30, Moriya discloses an EUV radiation source (Figure 2; [0057] “an exemplary configuration of the EUV light generation system 11A”) comprising:
a fuel emitter (Figure 2: element 26 is a target supply device; [0062]) configured to generate the plurality of targets (Figure 2; [0066] “target supply device 26 may be configured to output targets 27 in the form of droplets”), but does not specifically teach a laser beam system according to claim 24.
However, Moriya modified by Innes teaches a laser beam system according to claim 24 (see claim 24 rejection).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the EUV radiation source of Moriya, with a laser beam system according to claim 24, as taught by Moriya combined with Innes, because an EUV radiation system requires a high-power laser due to the fact that the specific 13.5 nm wavelength needed for advanced semiconductor manufacturing does not occur naturally in a usable, continuous state, and must be forced into existence through a specialized technique known as Laser-Produced Plasma (LPP).
Claim(s) 17-18, 20 and 23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Moriya et al. (US 2013/0119232 A1) and Innes et al. (US 6,219,146 B1) as applied to claim 16 above, and further in view of Müller et al., "Active sub-Rayleigh alignment of parallel or antiparallel laser beams," Opt. Lett. 30, 3323-3325 (2005); cited in IDS.
Regarding Claim 17, modified Moriya discloses the laser beam metrology system of claim 16, and the beam steering device (see claim 16 rejection), but does not specifically teach that the beam steering device comprises:
a first optical element configured to:
reflect the portion of the second laser beam pulse along the second direction,
receive the reflection of the first laser beam pulse, the reflection being reflected off of the target, and
reflect the portion of the reflection of the first laser beam pulse along a direction substantially opposite to the second direction;
a retro-reflector configured to:
receive the portion of the reflection of the first laser beam pulse, and
retro-reflect the portion of the reflection of the first laser beam pulse substantially along the second direction,
wherein the first optical element is further configured to:
receive the retro-reflected portion of the reflection of the first laser beam pulse, and
transmit a portion of the retro-reflected portion of the reflection of the first laser beam pulse substantially along the second direction, and
wherein the detection system is further configured to receive the portion of the retro-reflected portion of the reflection of the first laser beam pulse.
However, Innes, in the same field of optical alignment, teaches that the beam steering device (Figure 1: interferometric system element 90 [Column 3, line 67] and beamsplitter element 112 [Column 4, line 8] are interpreted as a beam steering device) comprises:
a first optical element (Figure 1: element 112 is a beamsplitter; [Column 4, line 8]) configured to:
reflect the portion of the second laser beam pulse along the second direction (Figure 1; [Column 4, lines 15-16] “reflect a beam portion 106b of laser beam 106 along a beam axis 114”),
receive the reflection of the first laser beam pulse (Figure 1: beamsplitter element 112 receives reflected beam portion 106a), the reflection being reflected off of the target (Figure 1; [Column 4, lines 11-12] “reflective surface 102, which reflects beam portion 106a back along a beam axis 124”), and
reflect the portion of the reflection of the first laser beam pulse along a direction (Figure 1; [Column 4, lines 13-14] “partially reflects beam portion 106a along a reflected beam axis 126”) substantially opposite to the second direction (Figure 1: reflected beam portion 106a along reflected beam axis 126 is substantially opposite to beam portion 106b along beam axis 114).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Innes, such that the beam steering device comprises: a first optical element configured to: reflect the portion of the second laser beam pulse along the second direction, receive the reflection of the first laser beam pulse, the reflection being reflected off of the target, and reflect the portion of the reflection of the first laser beam pulse along a direction substantially opposite to the second direction, because using a beamsplitter in laser alignment allows a single laser source to be distributed to multiple targets, maximizing a system's efficiency and alignment consistency.
Moriya is also silent with respect to a retro-reflector configured to:
receive the portion of the reflection of the first laser beam pulse, and
retro-reflect the portion of the reflection of the first laser beam pulse substantially along the second direction,
wherein the first optical element is further configured to:
receive the retro-reflected portion of the reflection of the first laser beam pulse, and
transmit a portion of the retro-reflected portion of the reflection of the first laser beam pulse substantially along the second direction, and
wherein the detection system is further configured to receive the portion of the retro-reflected portion of the reflection of the first laser beam pulse.
However, Müller, in the same field of optical alignment, teaches a retro-reflector (Figure 1: corner cube; [Page 1, Column 2]) configured to:
receive the portion ([Page 1, Column 2] “a ∼ 1% intensity sample”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection from a polarizing beam splitter (PBS)”), and
retro-reflect (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) the portion ([Page 1, Column 2] “a ∼ 1% intensity sample”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection from a polarizing beam splitter (PBS)”) substantially along the second direction (Figure 1: towards the right),
wherein the first optical element (Figure 1: PBS is a polarizing beam splitter; [Page 1, Column 2]) is further configured to:
receive the retro-reflected portion (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection”), and
transmit a portion (Figure 1; [Page 1, Column 2] “sample beams are directed to a QD”, wherein “QD” stands for quadrant detector) of the retro-reflected portion (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection”) substantially along the second direction (Figure 1: towards the right), and
wherein the detection system (Figure 1: quadrant detector) is further configured to receive the portion (Figure 1; [Page 1, Column 2] “sample beams are directed to a QD”, wherein “QD” stands for quadrant detector) of the retro-reflected portion (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection”).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Müller, for a retro-reflector configured to: receive the portion of the reflection of the first laser beam pulse, and retro-reflect the portion of the reflection of the first laser beam pulse substantially along the second direction, wherein the first optical element is further configured to: receive the retro-reflected portion of the reflection of the first laser beam pulse, and transmit a portion of the retro-reflected portion of the reflection of the first laser beam pulse substantially along the second direction, and wherein the detection system is further configured to receive the portion of the retro-reflected portion of the reflection of the first laser beam pulse, because “Two counterpropagating beams are aligned to produce zero misalignment error signals.” (Müller, Page 3, Column 1)
Regarding Claim 18, modified Moriya discloses the laser beam metrology system of claim 16, and the detection system (see claim 16 rejection), but does not specifically teach that the detection system is configured to:
direct the redirected portion of the reflection of the first laser beam pulse to a first sensor of the detection system, and
direct the reflected portion of the second laser beam pulse to a second sensor of the detection system.
However, Müller, in the same field of optical alignment, teaches that the detection system (Figure 1: quadrant detector) is configured to:
direct ([Page 3, Column 2] “For active control of the alignment by a proportional-integral (PI) feedback, we use a pair of mirrors that can be tilted by about 200 µrad using piezo actuators”) the redirected portion (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection from a polarizing beam splitter (PBS)”) to a first sensor (Figure 1: quadrant 3 or 4) of the detection system (Figure 1: quadrant detector), and
direct ([Page 3, Column 2] “For active control of the alignment by a proportional-integral (PI) feedback, we use a pair of mirrors that can be tilted by about 200 µrad using piezo actuators”) the reflected portion of the second laser beam pulse (Figure 1: red arrow indicates the reflected portion of the second laser beam pulse) to a second sensor (Figure 1: quadrant 1 or 2) of the detection system (Figure 1: quadrant detector).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Müller, such that the detection system is configured to: direct the redirected portion of the reflection of the first laser beam pulse to a first sensor of the detection system, and direct the reflected portion of the second laser beam pulse to a second sensor of the detection system, because directing different laser beams to distinct sensors—rather than grouping them onto a single target—allows systems to perform independent, simultaneous measurements, which prevents beam crossover interference, enables tracking of angular and positional errors, and ensures precise, independent optical calculations across complex setups.
Regarding Claim 20, modified Moriya discloses the laser beam metrology system of claim 17, wherein:
the first optical element (Figure 2: element 342 is a dichroic mirror; [0057]) is configured to transmit at least 90% (Figure 2; [0061] “dichroic mirror 342 may be coated on a first surface thereof with a film configured to … transmit the pre-pulse laser beam 41 with high transmittance”, wherein “high transmittance” is interpreted as at least 90%) of the second laser beam pulse (Figure 2: element 41 is a pre-pulse laser beam; [0059]), and
the first optical element (Figure 2: element 342 is a dichroic mirror; [0057]) is configured to transmit 10-90% or 40-60% of the reflection of the first laser beam pulse (Figure 2; [0061] “dichroic mirror 342 may be coated on a first surface thereof with a film configured to reflect the main pulse laser beam 32 with high reflectance”).
Regarding Claim 23, modified Moriya discloses the laser beam metrology system of claim 17, and the first optical element (see claim 17 rejection), but does not specifically teach that the first optical element comprises a first surface to receive the reflection of the first laser beam pulse and a second surface to receive the second laser beam pulse.
However, Innes, in the same field of optical alignment, teaches that the first optical element (Figure 1: element 112 is a beamsplitter; [Column 4, line 8]) comprises a first surface to receive the reflection of the first laser beam pulse (Figure 1: beamsplitter element 112 receives reflected beam portion 106a, along beam axis 124, on a first surface) and a second surface to receive the second laser beam pulse (Figure 1: beamsplitter element 112 receives laser beam 106 on a second surface).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Innes, such that the first optical element comprises a first surface to receive the reflection of the first laser beam pulse and a second surface to receive the second laser beam pulse, because in EUV systems, beam splitters are essential for the drive laser system that generates the EUV plasma, allowing engineers to sample and redirect 1% – 10% of the beam for real-time profiling, energy monitoring, and safety verification without causing significant power loss to the main beam used for tin droplet ignition.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Moriya et al. (US 2013/0119232 A1) and Innes et al. (US 6,219,146 B1) and Müller et al., "Active sub-Rayleigh alignment of parallel or antiparallel laser beams," Opt. Lett. 30, 3323-3325 (2005); cited in IDS, as applied to claim 18 above, and further in view of Van der Post (US 2019/0101840 A1).
Regarding Claim 19, modified Moriya discloses the laser beam metrology system of claim 18, the first sensor (see claim 18 rejection), the second sensor (see claim 18 rejection), and the detection system (see claim 16 rejection), but does not specifically teach:
the first sensor is configured to provide a first signal representing a position of the redirected portion of the reflection of the first laser beam pulse on the first sensor,
the second sensor is configured to provide a second signal representing a position of the reflected portion of the second laser beam pulse on the second sensor, and
the detection system comprises a processing unit, the processing unit configured to determine the relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse based on the first signal and the second signal.
However, Müller, in the same field of optical alignment, teaches:
the first sensor (Figure 1: quadrant 3 or 4) is configured to provide a first signal ([Page 2, Column 2] “signals from the quadrants”) representing a position (implicit for a quadrant detector to output a signal representing a relative position of a laser spot) of the redirected portion (Figure 1; [Page 1, Column 2] “retroreflection from the corner cube”) of the reflection of the first laser beam pulse ([Page 1, Column 2] “a residual reflection from a polarizing beam splitter (PBS)”) on the first sensor (Figure 1: quadrant 3 or 4), and
the second sensor (Figure 1: quadrant 1 or 2) is configured to provide a second signal ([Page 2, Column 2] “signals from the quadrants”) representing a position (implicit for a quadrant detector to output a signal representing a relative position of a laser spot) of the reflected portion of the second laser beam pulse (Figure 1: red arrow indicates the reflected portion of the second laser beam pulse) on the second sensor (Figure 1: quadrant 1 or 2).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Müller, wherein the first sensor is configured to provide a first signal representing a position of the redirected portion of the reflection of the first laser beam pulse on the first sensor, and the second sensor is configured to provide a second signal representing a position of the reflected portion of the second laser beam pulse on the second sensor, because by independently measuring and comparing the signal strengths from each quadrant, the detector can calculate the precise 2D position, intensity, and movement of a laser spot.
Moriya is also silent with respect to: the detection system comprises a processing unit, the processing unit configured to determine the relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse based on the first signal and the second signal.
However, Van der Post, in the same field of optical alignment, teaches that the detection system (Figure 1: element 20 is a specular detection branch detector; [0108]) comprises a processing unit ([0108] “data may be processed” is interpreted as presence of a processor), the processing unit configured to determine the relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse ([0108] “first and second sets of intensity data may be processed to determine one or more alignment properties of the illumination beam of radiation”, wherein “one or more alignment properties of the illumination beam of radiation” is interpreted as relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse) based on the first signal (Figure 1; [0108] “A first set of intensity data represents a projection of a first beam of radiation onto the pixelated sensor of the specular detection branch detector 20”, wherein “projection of a first beam of radiation onto the pixelated sensor” is interpreted as producing a first signal) and the second signal (Figure 1; [0108] “a second set of intensity data represents a projection of a second subsequent beam of radiation onto the pixelated sensor of the specular detection branch detector 20”, wherein “projection of a second subsequent beam of radiation onto the pixelated sensor” is interpreted as producing a second signal).
Therefore, it would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the metrology system of Moriya with the teachings of Van der Post, such that the detection system comprises a processing unit, the processing unit configured to determine the relative orientation between the reflection of the first laser beam pulse and the second laser beam pulse based on the first signal and the second signal, because “The determined alignment properties of the illumination beam of radiation may be used to control the substrate support … in order to adjust the position and propagation direction of the illumination beam of radiation to a target position and a target propagation direction.” (Van der Post, para 108)
Conclusion
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/AKBAR H. RIZVI/
Examiner, Art Unit 2877
/TARIFUR R CHOWDHURY/Supervisory Patent Examiner, Art Unit 2877
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