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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 August 11, 2026, has been entered.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3, 9, and 21-23 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Appl. Publ. No. 2014/0182511 to Rathod, et al. (hereinafter “Rathod”) in view of U.S. Patent Appl. Publ. No. 2006/0121068 to Sane, et al. (“Sane”) and further in view of U.S. Patent Appl. Publ. No. 2002/0086119 to Hariharan, et al. (“Hariharan”).
Regarding claim 1, Rathod teaches a method for producing a single crystal silicon ingot from a silicon melt (see the Abstract, Fig. 1, and entire reference which teach a method of growing a Si ingot from a Si melt) comprising:
providing a graphite susceptor having an interior surface defining a cavity (see Fig. 1, ¶¶[0003]-[0004], and ¶¶[0013]-[0014] which teach providing a graphite susceptor (102) having an interior cavity (104));
depositing a coating onto the interior surface of the susceptor, the coating comprising boron nitride (see Fig. 1 and ¶¶[0015]-[0017] which teach forming a coating (108) on an interior surface of the susceptor (102) which, in one embodiment, is comprised of boron nitride),
wherein depositing the coating includes spraying the boron nitride onto the interior surface of the susceptor (see Fig. 1 and ¶¶[0023]-[0028] which teach that the coating (108) may be sprayed onto the interior surface of the graphite susceptor (102));
positioning a quartz crucible in the cavity of the susceptor, the quartz crucible having an outer surface that contacts the coating (see Fig. 1, ¶¶[0003]-[0004], and ¶¶[0013]-[0015] which teach positioning a quartz crucible (110) into the cavity of the susceptor (102) such that the quartz crucible (110) contacts the coating (108));
adding polycrystalline silicon to the quartz crucible; heating the polycrystalline silicon to cause the silicon melt to form in the quartz crucible; and pulling the single crystal silicon ingot from the silicon melt (see ¶¶[0003]-[0005] which teach that polysilicon is added to the crucible (110), the polysilicon is heated to form a melt, and a single crystal is grown from as seed by slow extraction as part of the Czochralski crystal growth process).
Rathod does not teach that the coating comprises a sintering additive, wherein the sintering additive promotes densification of the boron nitride or the step of forming a coated particulate mixture comprising boron nitride particles coated with only the sintering additive. However, in Figs. 1-4 and ¶¶[0023]-[0059] and the Examples in ¶¶[0066]-[0076] as well as elsewhere throughout the entire reference Sane teaches a method of producing boron nitride (BN) powder particles in which the surface is covered with a coating comprised only of a material such as alumina. This is specifically taught in at least ¶[0046] and ¶¶[0050]-[0054] which teach that the process for producing the BN particles may be modified such that only an alumina coating is formed thereupon in order to, for example, improve the thermal conductivity and rheological properties of the BN particles. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to produce the BN coating utilized in the method of Rathod using BN particles coated only with an additive such as alumina in order to improve the thermal conductivity and/or to reduce the viscosity of the mixture such that a more uniform and consistent BN coating with a higher density may be formed on interior surfaces of the graphite susceptor (102) of Rathod.
Rathod and Sane do not teach the steps of plasma spraying the coated particulate mixture comprising the boron nitride particles coated with only the sintering additive onto the interior surface of the susceptor. However, in ¶¶[0023]-[0044] as well as elsewhere throughout the entire reference Hariharan teaches an analogous method of forming a protective layer between a quartz crucible and a graphite susceptor by plasma spraying. In ¶¶[0029]-[0032] Hariharan specifically teaches that the coating materials in powder form are fed into a plasma jet through one or more powder feeders along with a plasma gas which is in the form of argon, helium, nitrogen, hydrogen, or a combination thereof. In ¶[0030] Rathod further teaches that plasma spray deposition has the advantages of high efficiency in terms of throughput, processing step, energy, and ease of operation and is capable of depositing materials that have very high melting points. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to utilize plasma spraying to feed a powder mixture comprised of boron nitride and only the sintering additive as taught by Rathod and Sane through a plasma jet in order to efficiently deposit an uniform, consistent, and higher quality layer of the desired boron nitride coating onto the susceptor in the method of Rathod.
Regarding claim 3, Rathod and Hariharan do not teach that a mass ratio of the sintering additive to the boron nitride in the coating is from 1:20 to 1:1. However, in at least ¶[0053] Sane specifically teaches that the amount of oxide coating on the BN particles may range from 1 to 7 wt. % which overlaps the claimed range. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to utilize a protective coating comprised of up to 7% of alumina by weight as the sintering additive in order to improve the thermal conductivity and reduce the viscosity of the BN particles such that a more uniform BN layer and, consequently, a more effective barrier is formed between the graphite susceptor (102) and quartz crucible (110) of Rathod.
Regarding claim 9, Rathod does not teach that the sintering additive comprises silica, silicon carbide, boric acid, alumina, yttria, zirconia, aluminum nitride, lanthana, or a combination thereof. However, as noted supra with respect to the rejection of claim 1, in Figs. 1-4 and ¶¶[0023]-[0059] and the Examples in ¶¶[0066]-[0076] as well as elsewhere throughout the entire reference Sane teaches a method of producing boron nitride (BN) powder particles in which the surface is covered with a coating comprised only of a material such as alumina. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to produce the BN coating utilized in the method of Rathod using BN particles coated only with an additive such as alumina in order to improve the thermal conductivity and/or to reduce the viscosity of the mixture such that a more uniform and consistent BN coating may be formed on interior surfaces of the graphite susceptor (102) of Rathod.
Regarding claim 21, Rathod and Sane do not teach that the boron nitride particles coated with sintering additive are accelerated at a speed of 50 to 3000 m/s through a plasma jet. However, as noted supra with respect to the rejection of claim 1, in ¶¶[0023]-[0044] as well as elsewhere throughout the entire reference Hariharan teaches an analogous method of forming a protective layer between a quartz crucible and a graphite susceptor by plasma spraying. In ¶[0031] Hariharan specifically teaches that the powder particles are accelerated and heated up to velocities of 50 to 200 m/s and a temperature of about 2,000 to 3,000 °C. The high-speed softened or melted particles impact on the substrate surface and solidify rapidly to form the desired coating. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize the plasma spray deposition technique of Hariharan to accelerate the boron nitride and sintering additive particles of Rathod and Sane to a speed in the overlapping range of 50 to 200 m/s in order to cause the particle to impact onto the substrate surface and solidify rapidly into the desired coating.
Regarding claim 22, Rathod and Sane do not teach that the boron nitride particles coated with sintering additive are heated to a temperature between 2,000 °C and 3,000 °C through the plasma jet. However, as noted supra with respect to the rejection of claim 1, in ¶¶[0023]-[0044] as well as elsewhere throughout the entire reference Hariharan teaches an analogous method of forming a protective layer between a quartz crucible and a graphite susceptor by plasma spraying. In ¶[0031] Hariharan specifically teaches that the powder particles are accelerated and heated up to velocities of 50 to 200 m/s and a temperature of about 2,000 to 3,000 °C. The high-speed softened or melted particles impact on the substrate surface and solidify rapidly to form the desired coating. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize the plasma spray deposition technique of Hariharan to heat the boron nitride and sintering additive particles of Rathod and Sane to a temperature in the overlapping range of 2,000 to 3,000 °C in order to melt or soften the particles such that they impact onto the substrate surface and solidify rapidly into the desired coating.
Regarding claim 23, Rathod and Hariharan do not teach that the coated particulate mixture is formed by adding the sintering additive to an aqueous solution; washing the boron nitride particles with the aqueous solution comprising the sintering additive in a slurry; and drying the slurry to remove water. However, as noted supra with respect to the rejection of claim 1, in Figs. 1-4 and ¶¶[0023]-[0059] and the Examples in ¶¶[0066]-[0076] as well as elsewhere throughout the entire reference Sane teaches a method of producing boron nitride (BN) powder particles in which the surface is covered with a coating comprised only of a material such as alumina. In Fig. 1 and ¶¶[0066]-[0067] Sane specifically teaches a method of forming the BN particles in which an aqueous slurry (6) that includes the BN particles, a binder, and the sintering additive disclosed in ¶¶[0050]-[0054] is heated to a temperature of 250 to 360 °C before being injected at a desired feed rate into a spray drying chamber (1). The particles formed in the spray drying chamber (1) are then dried at an elevated temperature to produce a moisture level below 1% and are collected. Thus, a PHOSITA prior to the effective filing date of the invention would recognize that the coated BN powder particles utilized to form the BN coating in Rathod may be produced using a wet method which includes adding the BN particles and the sintering additive to an aqueous solution to form a slurry followed by drying the slurry with the motivation for doing so being to promote adhesion of the sintering additive to the surface of the BN particles such that a more uniform coating is obtained.
Response to Arguments
Applicants’ arguments filed August 11, 2026, have been fully considered, but they are moot in view of the new grounds of rejection set forth in this Office Action. U.S. Patent Appl. Publ. No. 2006/0121068 to Sane, et al. has been introduced in place of U.S. Patent Appl. Publ. No. 2007/0054122 to Paisner, et al. (“Paisner”) to teach BN particles coated with only the sintering additive as recited in amended claim 1. The Examiner notes that the material used to produce the reactive sites as well as the second coating formed thereupon in the method of Paisner may altogether be considered as part of the sintering additive as claimed. Consequently, in providing the claim with its broadest reasonable interpretation Paisner also teaches a process in which the BN particles are “only” coated with the sintering additive.
Conclusion
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714
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