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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 19 August 2025 has been entered.
Response to Arguments
Applicant’s arguments, see pages 9-15, filed 15 July 2025, with respect to the rejection(s) of claim(s) 1, 21, and 29 under 35 U.S.C. 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of US 2024/0142871 A1 (hereby referred to as Nikipelov).
Applicant has entered the amendments previously proposed in the after-final response filed 15 July 2025. No additional arguments are presented. As noted in the advisory action filed 31 July 2025, the amendments to the claims appeared to overcome the previously cited art, but additional search and consideration would be required to determine patentability of the amended claims. Refer to paragraphs 3-5 of the advisory action filed 31 July 2025 for the Examiner’s response to the Applicant’s arguments. The Applicant’s arguments are found to be persuasive in light of the claim amendments and therefore the previous rejection has been withdrawn. However, a new rejection is presented in view of US 2024/0142871 A1 (hereby referred to as Nikipelov), as explained below.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1, 3, 8-9, 21, 23, 29, and 31 are rejected under 35 U.S.C. 103 as being unpatentable over TW I576657 B (hereby referred to as TW ‘657) in view of US 2024/0142871 A1 (hereby referred to as Nikipelov).
The Examiner notes that whilst Nikipelov was published on 2 May 2024, the application was filed 25 August 2020 and claimed priority to EP application 19204036.8, which was filed on 18 October 2019. Thus, Nikipelov has an earlier effective filing date than the instant application and qualifies as prior art under 35 U.S.C. 102(a)(2).
Regarding Claims 1, 21, and 29, TW ‘657 discloses a photomask cleaning apparatus and method. The method first comprises detecting a mask via visual inspection, wherein the mask has a protective film (i.e. a pellicle) and the protective film has contaminants (TW ‘657, paragraph 0078 of the English translation). The mask is placed in a cleaning apparatus described by TW ‘657 (TW ‘657, paragraph 0078 of the English translation). A moving mechanism moves the mask in a direction and during this time an oscillation element, an ion generating element, and a gas jet head pass over the protective film (TW ‘657, paragraph 0080 of the English translation). The oscillating element vibrates the protective film using ultrasonic waves (TW ‘657, paragraph 0081 of the English translation). The ion generating element reduces static electricity between the contaminant and the protective film (TW ‘657, paragraph 0082 of the English translation) whilst the gas jet head ejects a gas stream to blow over the surface of the protective film (TW ‘657, paragraph 0083 of the English translation). The gas jet head is rotatable, allowing for the angle of the gas jet head towards the surface of the membrane to be adjusted (TW ‘657, paragraph 0073 of the English translation). Following the cleaning of the protective film, the mask is transferred to a semiconductor device (TW ‘657, paragraph 0088 of the English translation). TW ‘657 further discloses that a mask is used to pattern material layers and form circuit parts and components for semiconductor devices (TW ‘657, paragraph 0002-0003). TW ‘657 discloses that the pellicle frame is attached to an inner surface of the pellicle membrane (see Fig. 2 of TW ‘657, wherein M15 is the pellicle membrane and M14 is the pellicle frame). Furthermore, TW ‘657 discloses that the inside surface of the pellicle membrane faces the photomask (i.e. the reticle) (see Fig. 4A of TW ‘657, wherein M15 is the pellicle membrane and M1 is the photomask).
However, TW ‘657 does not disclose that the gas jet head flows gas onto the inside surface of the pellicle membrane, nor does TW ‘657 disclose that the membrane is separated from the reticle during the cleaning procedure. Nikipelov teaches a membrane cleaning apparatus and a method for removing particulate from a membrane. The membrane of Nikipelov is a pellicle for use in an EUV lithography apparatus (Nikipelov, paragraph 0009). Nikipelov teaches that before the pellicle is attached to a support structure or a patterning device (i.e. a reticle), the pellicle membrane may become dirty from particles present on the pellicle membrane (Nikipelov, paragraph 0060). It is thus implied by Nikipelov that the pellicle membrane is provided whilst not affixed to a reticle. The pellicle is provided to the membrane cleaning apparatus as shown in Fig. 2 of Nikipelov (Nikipelov, paragraph 0065-0067). The apparatus utilizes pressure pulses to dislodge particles from the membrane, which induce mechanical oscillations in the membrane (Nikipelov, paragraph 0063-0064). Nikipelov further teaches that the apparatus is configured to flow gas across one or both faces of the membrane, wherein the gas may be hydrogen, nitrogen, noble gases, or a mixture of gases (Nikipelov, paragraph 0029).
TW ‘657 and Nikipelov are analogous art because both references pertain to pellicles and cleaning methods. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to provide flow towards both surfaces of the pellicle membrane, as taught by Nikipelov, in the method disclosed by TW ‘657 because the application of gas to both the inner and outer surfaces of the pellicle, in addition to the mechanical oscillation of the membrane, allows for debris on the inner and outer surfaces of the pellicle to be dislodged and removed (Nikipelov, paragraph 0029). It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to perform the cleaning procedure whilst the pellicle is not affixed to a reticle, as taught and/or suggested by Nikipelov because activities such as transporting the pellicle, packaging the pellicle, and/or mounting the pellicle membrane to a frame may result in particles being incident upon the pellicle membrane (Nikipelov, paragraph 0060), and the detaching of the particles on membrane may result in the particles traveling to the patterning device (the reticle), thereby negatively affecting the pattern projected by the reticle (Nikipelov, paragraph 0061). In other words, cleaning the membrane whilst not affixed to the reticle prevents the particles/debris removed from the pellicle membrane from ending up on the surface of the reticle, improving the pattern accuracy of the reticle and mitigating defects. The Examiner notes that TW ‘657 discloses a rotatable gas nozzle, which allows for the angle between the gas flow and the surface of the membrane to be controlled (TW ‘657, paragraph 0073 of the English translation). Whilst the angles recited by instant claim 29 are not explicitly disclosed, one having ordinary skill in the art would find the angles obvious through routine optimization of the angle of the gas nozzle as taught by TW ‘657, wherein the skilled artisan would expect the angle of the gas flow to influence effectiveness of debris and/or particulate removal based on the mathematical principles that govern fluid mechanics (specifically, the force components in each relevant dimension obtained by changing the angle of the flow). Refer to MPEP 2144.05 II.
Regarding Claims 3 and 23, TW ‘657 discloses that the gas jet head (i.e. the gas nozzle) can extend along the direction D2 (see Fig. 4A) and is best described as a showerhead (TW ‘657, paragraph 0073 of the English translation). Combined with this disclosure and Fig. 4A, it is apparent that the jet head comprises a linear array that provides multiple streams of the gas. The Examiner notes that TW ‘657 discloses a rotatable gas nozzle, which allows for the angle between the gas flow and the surface of the membrane to be controlled (TW ‘657, paragraph 0073 of the English translation). Whilst the angles recited by instant claims 3 and 23 are not explicitly disclosed, one having ordinary skill in the art would find the angles obvious through routine optimization of the angle of the gas nozzle as taught by TW ‘657, wherein the skilled artisan would expect the angle of the gas flow to influence effectiveness of debris and/or particulate removal based on the mathematical principles that govern fluid mechanics (specifically, the force components in each relevant dimension obtained by changing the angle of the flow). Refer to MPEP 2144.05 II.
Regarding Claims 8 and 31, TW ‘657 discloses that the ultrasonic wave device generates ultrasonic waves having frequencies between 18 kHz and 2 MHz (TW ‘657, paragraph 0065 of the English translation).
Regarding Claim 9, TW ‘657 discloses that the gas dispensed is nitrogen gas (TW ‘657, paragraph 0072 of the English translation).
Claim(s) 2, 22, and 30 are rejected under 35 U.S.C. 103 as being unpatentable over TW I576657 B (hereby referred to as TW ‘657) in view of US 2024/0142871 A1 (hereby referred to as Nikipelov) as applied to claims 1, 21, and 29 above, and further in view of JP 2006339664 A (hereby referred to as JP ‘664).
Regarding Claims 2, 22, and 30, the combination of TW ‘657 and Nikipelov renders obvious a method of cleaning a photomask comprising a protective film, as discussed above. As described above, TW ‘657 utilizes a moving stage that holds the photomask and a gas nozzle in the cleaning apparatus.
However, TW ‘657 and Nikipelov are silent in regards to the utilization of two or more gas nozzles. JP ‘664 teaches a cleaning apparatus for cleaning a substrate (JP ‘664, paragraph 0001-0002 of the English translation). The apparatus taught by JP ‘664 includes two nozzles (“vapor knives”), wherein the nozzles are oriented such that the second nozzle is blowing gas in an opposite angle and in an opposite direction relative to the first nozzle (paragraph 0073 of the English translation and Fig. 8-9). JP ‘664 states in paragraph 0088 of the English translation that there is a time offset given to the sweeping of the liquid on the upper surface and the lower surface of the substrate, which is attributed to the upper vaper knife (VNU) and the lower vapor knife (VNL) not dispensing gas at the same time. This is interpreted as one gas nozzle flowing gas whilst the other gas nozzle is not supplying gas.
TW ‘657, Nikipelov, and JP ‘664 are analogous art because these references pertain to cleaning apparatuses and methods for photomasks and their components, such as substrates and/or pellicles. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to include a second nozzle that blows gas in an opposite angle and opposite direction to the first nozzle, as taught by JP ‘664, in the apparatus utilized in the method disclosed by combining TW ‘657 and Nikipelov because the opposing forces provided by the gas streams improve the effectiveness of the cleaning tool (see JP ‘664, paragraph 0089 of the English translation). It would have further been obvious to one having ordinary skill in the art before the filing date of the instant application to enable a nozzle blowing gas in a positive direction whilst the pellicle moves in a negative direction (and vice versa) because this would similarly increase the effects of opposing forces being applied to the particulate, thereby improving the effectiveness of the cleaning tool. For instance, the positive direction flow of the gas, when contacting the pellicle whilst moving in a negative direction, results in a force of greater magnitude on the particulate compared to when the pellicle is moving in the positive direction, or not moving at all. Lastly, it would have been obvious to one having ordinary skill in the art before the filing date of the instant application to flow gas from one nozzle whilst not flowing gas from the other nozzle because having an offset in the nozzle flows reduces or prevents contaminants from collecting at the rear end of the substrate (JP ‘664, paragraph 0088 of the English translation).
Claim(s) 4 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over TW I576657 B (hereby referred to as TW ‘657) in view of US 2024/0142871 A1 (hereby referred to as Nikipelov) as applied to claims 1 and 21 above, and further in view of US 2020/0249588 A1 (hereby referred to as Watanabe).
Regarding Claims 4 and 24, the combination of TW ‘657 and Nikipelov renders obvious a method of producing circuit patterns and pellicle cleaning, as described above. TW ‘657 discloses the use of gas flows to remove contaminants.
However, TW ‘657 and Nikipelov are silent in regards to the flow rate of the gas. Watanabe teaches an adhesive residue removal apparatus and an adhesive residue removal method. The method is used to clean a photomask assembly by converting oxygen contained in clean dry air into active oxygen radicals (Watanabe, paragraph 0010). Watanabe teaches that the clean dry air (CDA) has a flow rate between 3 L/min and 5000 L/min (Watanabe, Claim 3). Whilst this range is large, Watanabe teaches that the gas flow rate and the processing time are related in terms of the effectiveness of the cleaning procedure (see Watanabe, Fig. 3 and Fig. 4). When a large flow rate is provided over a long processing time, the mask may be damaged, but when the flow rate is provided under short processing times, the effectiveness of the cleaning may be insufficient (see Watanabe, Fig. 4). Thus, the mask may go undamaged with sufficient cleaning effectiveness when the flow rates are low and enough processing time is provided.
TW ‘657, Nikipelov, and Watanabe are analogous art because these references pertain to cleaning apparatuses and methods. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to use a gas flow rate between 2 L/min and 10 L/min (as recited by instant claims 4 and 24) in the method obtained by combining TW ‘657 and Nikipelov because a flow rate in this range can sufficiently clean the mask of residues and contaminants whilst preventing the mask from becoming damaged (see Watanabe, Fig. 3 and 4).
Claim(s) 5-7 and 25-28 are rejected under 35 U.S.C. 103 as being unpatentable over TW I576657 B (hereby referred to as TW ‘657) in view of US 2024/0142871 A1 (hereby referred to as Nikipelov) as applied to claims 1 and 21 above, and further in view of US 2002/0083957 A1 (hereby referred to as Reid).
Regarding Claims 5-7 and 25-28, the combination of TW ‘657 and Nikipelov renders obvious a method of cleaning a photomask having a protective film (i.e. a pellicle), as discussed above. In the method disclosed by TW ‘657, ionized gas is provided to the protective film to reduce static (TW ‘657, paragraph 0069 of the English translation).
However, TW ‘657 and Nikipelov are silent in regards to the specific mechanism of ionization. Reid teaches a method and apparatus for in-situ lithography mask cleaning. The method taught by Reid reduces particle contamination (Reid, paragraph 0015) by applying ionized gas to the surface of the mask (Reid, paragraph 0016). Reid teaches that the ionized gas may be produced by exposing a gas with alpha particles produced by a radioactive isotope, such as Polonium having an atomic weight of 210 (Reid, paragraph 0028). As stated in the instant application’s specification, Polonium-210 produces a radioactivity of at least 5 millicurie (mCi) (see paragraph 0025 of the instant application’s specification), thus making this property inherent to the material.
TW ‘657, Nikipelov, and Reid are analogous art because these references pertain to cleaning apparatuses and methods. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to produce the ionized gas used in the method obtained by combining TW ‘657 and Nikipelov using an alpha particle-emitting isotope, such as Polonium-210, as taught by Reid, because performing ionization of the gas using such a radioactive isotope is a well-known technique in the art (Reid, paragraph 0028, 0033, and 0035) and producing an ionized gas through this technique allows for particulate contaminants to be removed from the mask surface effectively (Reid, paragraph 0026).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Particles on Surfaces 1: Detection, Adhesion, and Removal (hereby referred to as Mittal), teaches particulate removal from solid surfaces. In particular, page 27 of Mittal teaches the effects of the angle of an applied force on the removal force of a particle. This excerpt of Mittal shows that it is known in the art of particulate removal that the angle of the applied force (such as the force resulting from a gas flowing from a nozzle) can be optimized to provide a greater particulate removal force. This phenomenon is considered relevant to the obviousness of the angle(s) of the nozzle(s) providing gas flow as recited by instant claims 3, 23, and 29.
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/JAYSON D COSGROVE/Examiner, Art Unit 1737
/JONATHAN JOHNSON/Supervisory Patent Examiner, Art Unit 1734