DETAILED ACTION
Election/Restrictions
Applicant’s election of claims 67-73 in the reply filed on January 26, 2026 is acknowledged. Because Applicant did not distinctly and specifically point out any supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)). Claims 61-66 and 74-80 are withdrawn from consideration.
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.
Claims 67-73 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter the inventor or a joint inventor regards as the invention.
Claim 67 is indefinite because it recites plates including a “first layer” having “at least one crystalline phase of from 90 to 99.8 % by volume of polycrystalline yttrium aluminum garnet (YAG)”. Although the instant disclosure repeatedly conveys that the layer is “phase pure” and discusses the layer having a very high percentage (e.g. 90 to 99.8 vol. %) of YAG, the claim currently only requires that “at least one crystalline phase” have the recited YAG content, rather than the entire layer. Therefore, a layer having, for example, 98 vol. % SiC or 98 vol. % of an amorphous phase, could meet the requirement so long as it had a region (e.g. a “crystalline phase” occupying 2 vol. % of the layer) that was 90 to 99.8 vol. % YAG. As such, it appears that the claim recites something different from what Applicant intended to be the inventive feature.
The claim is further indefinite because it recites “wherein the polycrystalline aluminum garnet comprises pores on the surface” and “wherein the pores occupy less than 0.2 % of the surface area”. These limitations are unclear because, although the “first layer” was established to have a surface, the discussion of pores and surface area appear to be with respect to the YAG phase, which as discussed above, is not required to make up a specific portion of “the surface”. As such, it is unclear if the discussion of pores and the area they occupy is intended to refer to the surface of the layer, as a whole, or only what is present in the YAG phase. Appropriate correction and/or explanation are required.
The meaning of “the pores occupy less than 0.2 % of the surface area” is also unclear because it is unclear if “surface area” is intended to refer to the area of a planar surface, wherein some parts (e.g. 0.2 % of the surface) of the planar surface are “missing” due to pores, or if it refers to the measure of an entire area of an exterior of a body, including all of its topographic features, wherein the pores contribute to the surface area. Appropriate correction and/or explanation are required. For the sake of compact prosecution, either interpretation is considered herein to be correct.
The meaning of claim 68 is unclear because it recites that “the polycrystalline aluminum garnet has a volumetric porosity of 0.1 to 3 %”. As there are both “pores” and gas distribution holes passing through the YAG on the front plate, it is unclear if the “volumetric porosity” refers to all voids in the YAG phase, which includes “pores” and “holes”, or only the “pores”. For the sake of compact prosecution, the claimed porosity is interpreted herein as only referring to the volume of “pores” rather than “holes”.
The meanings of claims 69 and 70 are unclear because they respectively recite that the polycrystalline yttrium aluminum garnet is present in an amount of 90 to 99.8 % by volume and 93 to 99.8 % by volume without specifying to what the recited volume percentages refer. Therefore, it is unclear if the “first layer”, the “at least one crystalline phase”, the structure as a whole, or something else is required to have the recited volume percentages of YAG.
The meaning of claim 71 is unclear because it recites that “the polycrystalline yttrium aluminum garnet has a purity of 99.995 % or higher” without specifying to what measure or what structure the recited purity percentage refers. Therefore, it is unclear if the “purity” is in terms of weight, atom percent, or some other measure, and if the “first layer”, the “at least one crystalline phase”, the structure as a whole, or something else is required to have the recited YAG purity. Appropriate correction and explanation are required.
Claims 72 and 73 are indefinite because they also recite limitations about the percentage of the surface area occupied by pores, which is unclear for the reasons discussed above.
Claims 68-73 are also indefinite because they depend from claim 67.
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 67-73 are rejected under 35 U.S.C. 103 as being unpatentable over Yamada (US PG Pub. No. 2003/0232221) in view of Yoshitomi (US PG Pub. 2003/0100434) and Chandrasekharan (US PG Pub. No. 2015/0315706).
Regarding claims 67, 68, 72, and 73, Yamada teaches a unitary sintered ceramic body comprising a first layer comprising yttrium aluminum garnet (“YAG”) and a second layer comprising alumina and yttria-stabilized zirconia (Table 3, Ex. 14; par. 139). The two layers demonstrate a difference in coefficient of thermal expansion (“CTE”) of less than 0.75 x 10-6/ °C (Table 3). The first layer necessarily has a surface and a surface area and, being made YAG, includes at least one crystalline phase of YAG.
Although Yamada does not explicitly teach that the YAG layer is polycrystalline, he does disclose that the YAG layer is made by molding a slurry including YAG powder (par. 124, 133, 139). As Yamada teaches no steps for forming a monocrystalline YAG phase, it is more likely than not that the layer of sintered YAG powder is polycrystalline because the YAG particles (and crystallites) are in a random orientation, and the YAG phase is a polycrystalline YAG phase. Furthermore, it would have been obvious to one of ordinary skill in the art to configure the YAG phase to be polycrystalline because doing so would be a selection from a very limited number of possibilities (i.e. two possibilities including polycrystalline or monocrystalline).
The teachings of Yamada differ from the current invention in that he does not explicitly teach determining the difference in CTE between layers in the claimed manner, which might produce a different result from Yamada’s methods. Yamada also does not discuss the claimed pore sizes or amount of surface area occupied by pores in the YAG layer. However, Yamada does disclose that the YAG layer is made by gel cast molding, which he discloses produces films with extremely low porosity (par. 124, 139). Yoshitomi further teaches that CTE mismatch between materials can undesirably cause distortion of semiconductor processing chamber components and that such components should have very low porosity, including a porosity of 0.1 % or less (i.e. “a volumetric porosity 0.1 % or less”), and reduced pore size in order to reduce the amount of particles that attach to pores and thus maintain a high exposure accuracy (par. 48, 52). Accordingly, it would have been obvious to one of ordinary skill in the art to reduce the difference in CTE amongst the different layers/portions of the Yamada’s ceramic component as much as possible, including configuring the layers/components to have a CTE difference of less than 0.75 x 10-6/°C, and to reduce pore size and porosity as much as possible, including configuring the pore size to be below 1.5 µm, configuring the volumetric porosity to be 0.1 % or less, and, correspondingly, achieving a percentage of surface area occupied by pores of less than 0.2 % or even less than 0.1 % of the surface area, in order to prevent distortion of the component as much as possible and to prevent adhesion/capture of unwanted particles as much as possible in order to maintain a high exposure accuracy, as taught desirable by Yoshitomi.
The teachings of Yamada also differ from the current invention in that he does not explicitly teach that the sintered ceramic body discussed above is part of a showerhead assembly with front and back plates structured and positioned as claimed. However, Yamada does teach that his products can be used as a corrosion-resistant member with holes, such as a shower plate in a semiconductor manufacturing apparatus (par. 7, 19, 20). Yamada’s Example 14 also shows very little difference in CTE between its layers and demonstrates no incidence of cracking or pealing when subjected to testing (Table 3), and Yamada teaches that that his ceramic bodies offer improved dimensional precision and productivity (par. 160). Chandrasekharan further teaches a shower head assembly including a backplate portion (202) comprising a gas inlet (220), a frontplate portion (204) opposite the backplate portion and comprising a plurality of gas distribution holes (232), and an inner volume (230) in communication with the gas inlet (220) and the gas distribution holes (132) (Fig. 2; par. 42). Chandrasekharan’s showerhead assembly is beneficial because it allows for a reduced overall volume, which can achieve reduced purge times, improved uniformity of gas flow, and improved throughput (par. 42, 51, and 52). Therefore, it would have been obvious to one of ordinary skill in the art to make a showerhead assembly having the structure described by Chandrasekharan and discussed above and including plates (i.e. a frontplate with gas distribution holes, a backplate with a gas inlet, wherein the holes and inlet are in communication with an internal volume) each made of the layered ceramic disclosed by Yamada because Yamada teaches making showerhead components from his ceramics, exemplifies a ceramic that demonstrates little or no difference in CTE between its layers and, as a result, avoids cracking and peeling due to CTE mismatch, and discloses that his ceramics offer improved dimensional precision and productivity, and because Chandrasekharan discloses that his low-volume showerhead achieves reduced purge times, improved uniformity of gas flow, and improved throughput.
Regarding claims 69-71, the teachings of Yamada might be considered to differ from the current invention in that he does not explicitly teach that the volume percentage of YAG in his product or teach that the YAG has a purity of 99.995 % or higher. However, as Yamada makes his YAG layer from YAG particles (par. 124, 139) and makes no disclosure of there being other types of particles present, the layer is presumed to be substantially all, including greater than 90 or 93 vol. % YAG. Additionally, Yamada teaches that the content of impurities and other components is preferably 10 % by weight or less (par. 102), meaning that the YAG content should be 90 % by weight or greater. Therefore, the instantly claimed YAG purity is overlapped and rendered obvious by Yamada. See MPEP 2144.05. Furthermore, the requirement of a particular purity does not distinguish the claimed invention over the prior art because it is prima facie obvious to purify an old product that is taught by the prior art, particularly in view of Yamada’s rendering obvious 0 wt. % impurities. See MPEP 2144.04 VII.
As Yamada renders obvious making the weight percentage of impurities in his YAG layer as low as possible (including 0 wt. %, which also contains 0 vol. % impurities), he also effectively teaches making the volume percentage of impurities as low as possible, and, therefore, making the volume percentage of YAG as high as possible, including near 100 vol. %, within a layer. As such, it would have been obvious to one of ordinary skill in the art to configure Yamada’s YAG layer to have as high of a weight percentage of YAG as possible, thereby making it have as high of a volume percentage of YAG as possible, because Yamada teaches no lower limit to the amount of impurities that may be present. The recited volume percentages are obvious in view of Yamada’s teachings because they are sufficiently close to 100 % YAG, which is in view of obvious by Yamada for the reason discussed above. See MPEP 2144.05.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JULIA L RUMMEL whose telephone number is (571)272-6288. The examiner can normally be reached Monday-Thursday, 8:30 am -5:00 pm PT.
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/JULIA L. RUMMEL/
Examiner
Art Unit 1784
/HUMERA N. SHEIKH/ Supervisory Patent Examiner, Art Unit 1784
Prosecution Insights