DETAILED ACTION
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 69 is rejected under 35 U.S.C. 112(d) as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
As claim 66 now recites “the at least one first layer comprising from 90 to 99.8 % by volume of polycrystalline yttrium aluminum garnet (YAG)”, the claim 69 requirement that “the polycrystalline yttrium aluminum garnet (YAG) of the at least one first layer is present in an amount of 90 to 99.8 % by volume” fails to further limit claim 66. Appropriate correction is required. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Ther rejections made under 35 U.S.C. 112(b) in the previous Office Action are withdrawn in view of Applicant’s amendment, filed July 22, 2026.
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 67-73, 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 might be considered to differ from the current invention in that he does not explicitly teach the volume percentage of YAG in the first layer 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 reasons discussed above. See MPEP 2144.05.
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.
Response to Arguments
Applicant's arguments filed July 22, 2026 have been fully considered but they are not persuasive.
Applicant has argued that Yamada does not teach or suggest 90 to 99.8 vol % polycrystalline yttrium aluminum garnet (YAG) in a first layer. However, as discussed above, it would have been obvious to make such a layer because Yamada teaches a method of making the layer that is more likely than not to produce a polycrystalline YAG layer, makes no disclosure of a monocrystalline layer or processes to a achieve monocrystalline layer, and teaches making the layer to have less than 10 wt. % impurities, which renders obvious making the layer to have as high of a weight percentage and as high of a volume percentage of YAG as possible. It further would have been obvious for the reasons discussed above in view of Yoshitomi to configure the layer to have a porosity 0.1 % or less. Therefore, the combination of Yamada and Yoshitomi’s teachings renders obvious a first layer that is at least 99.9 vol. % solid material (i.e. 99.9 % dense) and 90 to 100 wt. % YAG, which encompasses and renders obvious a layer that is 90 to 99.8 vol. % polycrystalline YAG. See MPEP 2144.05.
Applicant has further argued that Yamada does not teach the recited maximum pore size, only provides porosity teachings related to a bulk material, and does not recognize that surface pores are problematic for a plasma-facing surface. However, it would have been obvious in view of Yoshitomi’s teachings to configure the pores in Yamada’s first layer to be present in at a level of 0.1 % or less and to be as small as possible, both of which apply to the whole layer, including its surface, to prevent adhesion/capture of unwanted particles, which is a surface process, as much as possible in order to maintain a high exposure accuracy, as taught desirable by Yoshitomi. Therefore, the prior art does appear to recognize the value of limiting porosity and pore size at the surface of a ceramic material used in a plasma processing component. Furthermore, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
Applicant has further argued that Yoshitomi actually teaches away from the product of claim 67 because his disclosure focuses on low thermal-expansion ceramics that may have additives, accepts a porosity of up to 0.5 vol. %, and focuses on bulk properties, which Applicant asserts would lead away from making a high-purity, low-surface porosity YAG ceramic. However, Yoshitomi was not cited for his teachings of a type of ceramic, but rather for his teachings about the relationships between dissimilar components’ thermal expansion coefficients and the porosity of a material in a semiconductor processing apparatus, both of which are applicable to Yamada. Yoshitomi also teaches that a porosity of 0.1 % or less is preferable (par. 52), which would be obvious to apply to an entire material or layer, including its surface. Yoshitomi cannot be construed as teaching away from the product of claim 67 or Yamada’s teachings because Yoshitomi’s teachings do not criticize, discredit, or otherwise discourage the claimed product or its structure, properties, or features.
Applicant has further argued that one skilled in the art would not be motivated to modify Yamada’s teachings based on those of Chandrasekharan because Chandrasekharan’s teachings are primarily directed to the hardware geometry and fluid dynamics of a showerhead, rather than ceramic structure or chemistry. However, the rejection is based on the grounds of making a showerhead assembly of Chandrasekharan’s design with Yamada and Yoshitomi’s material due to the advantages disclosed by each and Yamada’s explicit teaching of using his material as a shower plate of a semiconductor manufacturing apparatus. Therefore, the combination of Yamada and Chandrasekharan, as discussed in the rejection, follows Yamada’s teachings. As such, it would have been obvious to utilize Yamada and Yoshitomi’s ceramic material in Chandrasekharan’s showerhead assembly for the reasons discussed above.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/JULIA L. RUMMEL/
Examiner
Art Unit 1784
/HUMERA N. SHEIKH/Supervisory Patent Examiner, Art Unit 1784
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