DETAILED ACTION
Specification
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
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.
Claims 1-20 are 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 1 recites a first step of exposing a soot body to a constant steam pressure during which the partial pressure of steam is from about 0 Torr to about 760 Torr. A partial pressure of 0 Torr implies no steam. Thus, it is unclear how the soot body can be exposed to steam when the partial pressure of steam is at 0 Torr.
By virtue of their dependencies on claim 1, claims 2-20 are also considered indefinite.
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)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-14, and 16-20 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Campion et al. (2025/0178945). Regarding claim 1, Campion discloses a method for producing a titania-doped silica glass body, the method comprising exposing a titania-doped silica soot body to a constant steam pressure during which the partial pressure of steam is at a first partial pressure of steam P1 that is from about 0 Torr to about 760 Torr, and exposing the soot body to a ramp-up steam pressure step during which the partial pressure of steam increases from the first partial pressure of steam P1 to a second partial pressure of steam P2 (33.33kPa = 250 Torr), the second partial pressure of steam P2 being from about 50 torr to about 760 Torr, the second partial pressure of steam P2 being greater than the first partial pressure of steam P1, as depicted by the dotted line in figure 13 ([0152]-[0153]). Campion further teaches heating the soot body during the constant steam pressure step and the during the ramp-up steam pressure step, and increasing a temperature during at least one of the constant steam pressure step and the ramp-up steam pressure step, such as from 800°C to 1030°C, or from 1030°C to 1134°C (calculated from the rate of 2.5°C/hr in [0152], figure 13). Note, the constant steam pressure is interpreted to be satisfied by any of the initial partial pressure values before reaching the target of 33.33kPa in figure 13, including the initial value of 0 Torr and any small incremental value (i.e. 1 Torr) at the beginning of the ramp-up (along the vertical portion of dotted line 1320 in figure 13).
The applied reference has a common assignee with the instant application. Based upon the earlier effectively filed date of the reference, it constitutes prior art under 35 U.S.C. 102(a)(2). This rejection under 35 U.S.C. 102(a)(2) might be overcome by: (1) a showing under 37 CFR 1.130(a) that the subject matter disclosed in the reference was obtained directly or indirectly from the inventor or a joint inventor of this application and is thus not prior art in accordance with 35 U.S.C. 102(b)(2)(A); (2) a showing under 37 CFR 1.130(b) of a prior public disclosure under 35 U.S.C. 102(b)(2)(B) if the same invention is not being claimed; or (3) a statement pursuant to 35 U.S.C. 102(b)(2)(C) establishing that, not later than the effective filing date of the claimed invention, the subject matter disclosed in the reference and the claimed invention were either owned by the same person or subject to an obligation of assignment to the same person or subject to a joint research agreement.
Regarding claims 2-4, Campion discloses annealing the soot body after heating the soot body ([0039], [0134]). Campion also teaches a peak-to-valley difference of hydroxyl concentration amongst a plurality of segments of the body is less than 50 ppm, the hydroxyl concentration being measured using a Fourier transform infrared spectroscopy in transmission, and the plurality of segments including every adjacent segment across a length and a width of the body, the length being about 25 mm or more and the width being about 25 mm or more (abstract, [0094]-[0095]).
Regarding claims 7-8, Campion teaches the average hydroxyl concentration of the segments is between 50 ppm to 2000 ppm, which includes values of less than 400ppm ([0011]).
Regarding claim 9, Campion teaches after annealing, a peak-to-valley difference of titania concentration amongst the plurality of segment of the body is about 0.0100 wt% or less ([0113], [0114]).
Regarding claim 10, as mentioned above, since P2 is 33.33lPa (250 Torr) and the partial pressure of steam P1 is any of the pressure value at the beginning of the ramp-up, then P1 falls within the range of 5 Torr to 300 Torr.
Regarding claim 11, the partial pressure of steam P2 is 250 Torr ([0152]), which falls within the range of 200 Torr to 700 Torr
Regarding claims 12-13, as seen in figure 13, the temperature is increased during at least the ramp-up steam pressure step (from t=4000 mins to t= 6000 mins) and the constant steam pressure step (from t=2000 mins to t= 2000 mins + a few minutes).
Regarding claim 14, from figure 13 the time duration of the ramp-up steam pressure step is over 6000 mins (from about 2000mins to 8400 mins, [0152]), which is greater than a time duration of the constant steam pressure step, which can be as little as just a few minutes (vertical sloped dotted line) or as much as 2000 mins (if P1 is 0 Torr).
Regarding claim 16, heating the soot body during the constant steam pressure step comprises heating the soot body at a constant temperature T1 of 800°C (from t=544 mins to t=2000 mins).
Regarding claim 17, increasing the temperature begins at the start of the ramp-up steam pressure step (from t= 2000 mins to when T=1030°C is reached, [0152], figure 13).
Regarding claim 18, increasing the temperature begins before the start of the ramp-up steam pressure step (from t=0 mins to t=565 mins, [0152]).
Regarding claim 19, increasing the temperature comprises exposing the soot body to a temperature of 1030°C which is considered from about 1050°C ([0152]).
Regarding claim 20, the glass body is a photomask ([0081]).
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 11-13, 16, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Koike et al. (2010/0261597). Regarding claim 1, Koike discloses a process for forming a titania-silica glass body, the process comprising exposing a titania-doped silica soot body to a constant steam pressure during which the partial pressure of steam is at a first partial pressure of steam P1 that is from about 0 Torr to about 760 Torr, the constant steam pressure provided for by a normal atmosphere comprising He gas and water vapor ([0104]), and exposing the soot body, during densification, to a second pressure step during which the partial pressure of the steam is at a second partial pressure of steam P2 in the range of 10,000 Pa - 200,000 Pa (75 Torr - 1500Torr), which overlaps with the clamed range of 50 Torr to 760 Torr ([0063], [0105]). Koike also teaches heating the soot body during both exposing steps and increasing the temperature during at least one of the exposing steps, i.e. from 1000°C to 1450°C ([0104]-[0105]). Since the second exposure is performed at a much higher partial pressure, i.e. 75 torr-1500 Torr, than the first exposure step, i.e. normal atmosphere (760 Torr), and densification follows the first exposure step ([0066], [0105]), then it would be obvious to one of ordinary skill in the art at the time of the invention to have expected the second partial pressure of steam P2 to be greater than the first partial pressure of steam P1, and to provide for the step of ramping up from the first partial pressure P1 to the second partial pressure P2 for the subsequent step of densification. More specifically, in example 1, the porous body is densified in the same atmosphere of inert gas and steam as the first exposure step ([0104]-[0105]). Also, in the example, the total pressure in the first exposing step is normal pressure, which provides for a partial pressure of steam of less than 760 Torr. Combined with the suggestion that densification is performed with a partial pressure of steam P2 of 10,000 Pa - 200,000 Pa (75 Torr - 1500Torr), a second partial pressure of steam P2 that is greater than P1 is fairly suggested or obvious to one skilled in the art.
Regarding claim 11, the partial pressure of steam P2 is 10,000 Pa - 200,000 Pa (75 Torr - 1500Torr), which overlaps with the range of 200 Torr to 700 Torr ([0063]).
Regarding claims 12-13, the temperature is increased during at least the ramp-up steam pressure step (i.e. raised to 1450°C [0105]) and the constant steam pressure step (i.e. raised to 1000°C, [0104]).
Regarding claim 16, heating the soot body during the constant steam pressure step comprises heating the soot body at a constant temperature T1 of 1000°C ([0104])
Regarding claim 18, Koike teaches increasing the temperature to 1000°C begins before densification, which is before the start of the ramp-up steam pressure step needed for densification ([0104]).
Regarding claim 20, the glass body is a photomask ([0004]).
Claims 2-9 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Koike et al. (2010/0261597) as applied to claim 1 above, and further in view of Maida et al. (2008/0305941). Regarding claim 2, Koike discloses annealing the soot body after heating the soot body ([0072]-[0074]). Koike also teaches a need to reduce a variation in the coefficient of thermal expansion in the glass, which is closely tied to a variation of fictive temperature ([0046]-[0047]). Koike teaches measuring the variation in fictive temperature within an area of 50 mm by 50 mm ([0048]) and teaches controlling the fictive temperature by incorporating OH into the glass ([0051]) by steam doping ([0054]). Koike elaborates by keeping the variation in fictive temperature low and the variation in the hydroxyl concentration to 50 ppm or lower ([0057]). Thus, Koike appear to suggest keeping a low difference of hydroxyl concentration in the measured area. However, Koike doesn’t specify how to measure the peak-to valley difference of the hydroxyl concentration. Maida also teaches a method for producing a titania silica glass body, the method comprising annealing the titania silica glass body ([0042]). Maida further teaches the titania silica glass body has a hydroxyl group content and a peak-to-valley difference of hydroxyl concentration amongst a plurality of segments of the body is about 70 ppm or less (see examples 1-2 in Table 2), wherein the hydroxyl concentration is measured using a Fourier transform infrared spectroscopy in transmission ([0033]), and the plurality of segments including every adjacent segment across a length and a width of the body, the length being that is more than 25 mm and the width that is more than 25 mm (figure 2, [0045]). Like Koike, Maida teaches reducing a variation in the fictive temperature, and hence the coefficient of thermal expansion in the glass, to improve the stability of the glass ([0016], [0012]-[0013]). Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to have provided for similar low peak-to valley difference of the hydroxyl concentration of less than 70 ppm, measure by using Fourier transform infrared spectroscopy in transmission, so as to enhance stability of the glass.
Regarding claims 3-4, as mentioned above, Koike teaches a variation in the hydroxyl concentration to 50 ppm or lower ([0057]). Also, as seen in table 2 of Maida, the peak-to valley difference of the hydroxyl concentration is about 50 ppm.
Regarding claims 5-6, the sample of Maida has a length and width of 152.4 mm, which is greater than 100 mm ([0045]).
Regarding claims 7-8, Koike a OH concentration of at least 100 ppm or more ([0037]) which includes 100 ppm. Maida also teaches in example 2, a OH concentration of 70 ppm.
Regarding claim 9, Maida teaches after annealing, the peak-to-valley difference of titania concentration amongst the plurality of segment of the body that is about 0.0100 wt% ([0022]).
Regarding claim 17, since densification requires the increasing of the temperature, and Maida teaches increasing the partial pressure for densification, it would have been obvious to one of ordinary skill in the art at the time of the invention to have increased the temperature at the start of the ramp-up steam pressure step.
Claims 1-12, 14, 16-17 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Annamalai et al. (2016/0137545) in view of Campion (2025/0171345). Regarding claim 1, Annamalai disclose a method for producing a titania-silica body comprising exposing a titania-doped silica soot body to a constant steam pressure step during which the partial pressure of steam P1 is 0.2 atm (152 Torr) or less, which falls within the claimed range of from 0 Torr to about 760 Torr ([0142], [0144]), exposing the soot body to a second exposure step during which the soot body is consolidated ([0142]), heating the soot body during the exposure steps ([0146], [0147]) and increasing the temperature during at least one of the exposure steps, to reach the consolidation temperature ([0148]). Annamalai is silent regarding ramping up the steam pressure from a first partial of steam P1 to a second partial pressure of steam P2, wherein P2 is greater than P1. Campion also teaches a method for producing a titania-silica glass body, the method comprising exposing a titania-doped silica body ([0062]) to an atmosphere comprising steam ([0079]). Campion further teaches adjusting the partial pressure of steam during heat treatments to maintain high hydroxyl group concentration uniformity in the glass article, and suggests increasing the partial pressure steam when the temperature is increased ([0080]). Champion teaches in figure 9 a correlation between the partial pressure of steam and the temperature of the glass. For example, in the correlation line 940, at a first exposure treatment temperature of 900°C or below (as suggested by Annamalai), the partial pressure of steam P1 should be about 15 kPa (112 Torr) and the partial pressure of steam P2 during the consolidation temperature of 1500 °C (as suggested by Annamalai) should be about 40 kPa (300 Torr), which is within the claimed range for P2 of 50 Torr to 760 Torr (figure 9, [0135]). Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to have increased the partial pressure from P1 to P2, wherein P2 is greater than P1, when performing the densification step in the method of Annamalai, since densification is performed at a higher temperature, as suggested by Campion, thereby ensuring a uniform hydroxyl group concentration in the silica body.
Regarding claims 2 and 5-6, Annamalai discloses annealing the soot body after heating the soot body ([0042]). Campion also appears to suggest an annealing step ([0079]). Campion further teaches a peak-to-valley difference of hydroxyl concentration amongst a plurality of segments of the body is about 70 ppm or less, the hydroxyl concentration being measured using a Fourier transform infrared spectroscopy in transmission ([0090], [0092]), and the plurality of segments including every adjacent segment across a length and a width of the body, the length that is greater than 100 mm and the width that is greater than 100 mm ([0065]). Campion teaches the low peak-to-valley difference of hydroxyl concentration is an improvement to the hydroxyl group concentration uniformity, which provides for increased thermal stability to the glass article. Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to have provided for low peak-to-valley difference of hydroxyl concentration to the glass body of Annamalai so as to provide for increased thermal stability to the glass body.
Regarding claims 3-4, Champion discloses the peak-to valley difference of the hydroxyl concentration is less than 50 ppm ([0090]).
Regarding claims 7-8, Annamalai teaches the glass has a hydroxyl concentration between 100 ppm to 1350 ppm, which includes values of less than 400 ppm ([0192]). Campion also teaches the average hydroxyl concentration of the segments is between 50 ppm to 1,500 ppm, which includes values of less than 400ppm ([0098]-[0099]).
Regarding claim 9, Campion teaches after annealing, a peak-to-valley difference of titania concentration amongst the plurality of segment of the body is 30 ppm – 200 ppm, which includes values of about 0.0100 wt% or less ([0102], [0107]).
Regarding claim 10, Annamalai teaches the partial pressure of steam P1 is 0.2 atm or 152 Torr ([0144]), which falls within the range of 5 Torr to 300 Torr.
Regarding claim 11, as discussed above, Champion teaches a partial pressure of steam P2 of 300 Torr, which falls within the range of 200 Torr to 700 Torr.
Regarding claims 12, Annamalai teaches performing the first exposure step with P1 at a temperature in the range of 300°C to 700°C ([0146]) and then increasing the temperature to a temperature in the range of 900°C to 1500°C for consolidation ([00148]), and Champion suggests increasing the steam partial pressure during an increase in the temperature ([0135]). Thus, the temperature is increased during at least the ramp-up steam pressure step.
Regarding claim 14, Annamalai teaches the time duration of the ramp-up steam pressure step can be at least 0.5 hr, at least 1 hr, at least 2 hrs, or at least 5 hrs ([0147]). Similarly, Annamalai teaches the constant steam pressure step can be at least 0.5 hr, at least 1 hr, at least 2 hrs , or at least 5 hrs (0146]). Although, Annamalai doesn’t specify a time duration for the ramp-up steam pressure step that is greater than a time duration of the constant steam pressure step, it would have been obvious to one of ordinary skill in the art at the time of the invention to have tried any of the combination of time durations suggested, including a higher time duration for the ramp-up steam pressure step and lower time duration for the constant steam pressure step, as Annamalai teaches a limited number of solutions to try, with a reasonable expectation of success.
Regarding claim 16, Annamalai teaches heating the soot body during the constant steam pressure step comprises heating the soot body at a constant temperature T1, i.e. 700°C for 1 hour ([0146]).
Regarding claim 17, Champion suggests increasing the steam partial pressure during an increase in the temperature ([0135]). Thus, the temperature is increased at the start of the ramp-up steam pressure step.
Regarding claim 19, Annamalai teaches increasing the temperature comprises exposing the soot body to a temperature in the range of 900°C to 1300°C ([0147]), which provides for values that significantly overlap with the claimed range of from about 1050°C to about 1250°C.
Regarding claim 20, Annamalai discloses the glass body is a photomask ([0085]).
Allowable Subject Matter
Claim 15 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: the prior art teaches exposing a titania-doped silica soot body to an atmosphere comprising steam while heating and increasing the partial pressure of steam from a first partial pressure P1 to a higher partial pressure P2. However, the prior art fails to suggest increasing the steam pressure during the ramp-up steam pressure step at a rate of about 0.1 Torr/hr to about 10 Torr/hr.
Conclusion
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/QUEENIE S DEHGHAN/Primary Examiner, Art Unit 1741