DETAILED ACTION
Applicant’s Response
Acknowledged is the applicant’s request for reconsideration filed on September 2, 2025. Claim 1 is amended; claim 4 is canceled.
The applicant contends that the cited prior art does not properly disclose the new material incorporated into claim 1 from previous claim 4 – namely, a metal barrier layer comprising one of “silicon nitride, titanium nitride, tantalum nitride, or aluminum oxide.” Although Nishitani contemplates a barrier layer comprising aluminum oxide, the reference ultimately rejects this compound due to “insufficient shielding performance” [0040]. Thus, Nishitani explicitly teaches away from the use of aluminum oxide (p. 6).
In response, the examiner wishes to clarify the grounds of rejection which, in this case, are plural. First, as elaborated under the rejection of claim 1 in the previous Office letter, the claimed feature of the metal barrier layer may be understood as a product generated by the operator-directed use of the composite prior art apparatus. For instance, an operator can supply Ackerman’s material sources (9, 11) with the appropriate compounds and then control the metal furnace to deposit the metal barrier layer as an in situ process. In other words, Ackerman’s apparatus is inherently capable of fabricating the structural feature of the “metal barrier layer” through an in situ deposition process prior to the ingress of a workpiece, where the means by which the prior art derives said feature is not germane to the patentability of the apparatus – it has been held that a recitation drawn to the intended manner of employing a claimed apparatus does not differentiate said apparatus from a prior art apparatus satisfying the claimed structural limitations (Ex parte Masham, 2 USPQ2d 1647 (1987)). Of course, the selection of the compounds to charge Ackerman’s source containers (9, 11) is also a matter of intended use, where the operator can simply choose those chemicals which will generate one of a silicon nitride, tantalum nitride, titanium nitride, or aluminum oxide coating.
Regarding the second grounds of rejection, the examiner notes that Nishitani explicitly discloses the application of an aluminum oxide coating to the inner wall of the furnace tube [0037]. As the applicant observes, the durability of the aluminum oxide coating is ultimately deemed inferior to an alternative compound, but this is not germane. The fact remains that Nishitani has publicly disclosed the act of applying an aluminum oxide barrier layer to the interior of a metal furnace tube, as claim 1 requires, and the observation that another compound may demonstrate greater durability does not subvert this deliverance.
Third, the examiner observes that Nishitani’s preferred barrier layer comprises chromium oxide, which shares several similarities to the claimed compound of aluminum oxide [0038-39]. Due to comparable crystalline structures, both demonstrate thermal and chemical stability, corrosion and oxidation resistance, and serve as effective diffusion barriers. As such, the Office considers these compounds to be obvious over the other for the purpose of forming a barrier layer, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice (In re Leshin, 125 USPQ 416).
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 of this title, 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 1, 3, 5, 7-8, 10, and 32 are rejected under 35 U.S.C. 103 as being unpatentable over Ackerman, US 5,547,706, in view of Reynolds et al., US 3,183,130, and Nishitani et al., US 2012/0258565.
Claims 1, 5: Ackerman discloses an apparatus, comprising:
A horizontal furnace tube (1) having a first end and an opposing second end, including:
An inner chamber configured to support a plurality of substrates (35) (Fig. 1);
A fluid inlet (21) configured to intake a fluid;
A fluid outlet (25) configured to exhaust the fluid;
A heater (7) disposed outside the furnace tube (3, 40-45);
A first backing plate (3) comprising a first plurality of holes to accommodate screws which attach the plate to the first end of the furnace tube (3, 15-21);
A second backing plate (5) comprising a second plurality of holes to accommodate screws which attach the plate to the second end of the furnace tube.
As noted above, Ackerman avails “screws” to affix the backing plates to their corresponding end of the furnace tube, whereas claim 1 recites “bolts.” The examiner understands these fastening mechanisms to be obvious over the other.
Regarding the recitation of a “metal barrier layer covering an inner wall of the metal furnace tube,” an operator can simply provide the appropriate source material to Ackerman’s fluid inlet and then control the apparatus to form a barrier layer of the appropriate specification, in situ, on the inside surface of the furnace tube prior to the introduction of a workpiece.
Continuing, Ackerman’s fluid inlet and outlet are formed at the bottom of the furnace tube; thus, the backing plates do not “couple” the fluid inlet and outlet to the inner chamber, as claim 1 requires. Alternative configurations are known, however, as Reynolds demonstrates. Reynolds provides a furnace tube in which the fluid inlet feeds directly into a first backing plate (33) and the fluid outlet stems directly from a second backing plate (32) (Fig. 1). Further, the reference encloses a heater (42) within a furnace cabinet (30) filled with the insulating material of air (3, 25-75). It would have been obvious to the skilled artisan to configure the fluid inlet and outlet in accordance with Reynolds’ paradigm, as it is obvious to select from a finite number of predictable solutions with a reasonable expectation of success.
Lastly, Ackerman is silent as to the material composition of the furnace tube. Nishitani, however, teaches an analogous reaction tube structure and attests that conventional materials, like quartz, are expensive to produce and easily cracked [0007]. As a solution, the reference prescribes the use of stainless steel due to its durability and ease of manufacture [0008, 0030]. Further, Nishitani coats the interior of the metal furnace tube with aluminum oxide to provide a barrier layer [0037]. Given that Ackerman shares these desiderata, it would have been obvious to form the furnace tube of steel and provide a metal barrier layer, as it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice (In re Leshin, 125, USPQ 416).
Claim 3: Nishitani first roughens the inner surface of the furnace tube and then applies an oxide coating, thereby suppressing corrosion [0048-49]. Regarding the precise value of surface roughening: it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art (In re Boesch, 617 F.2d 272, 205 USPQ 215, CCPA 1980).
Claim 7: Ackerman’s furnace tube is capable of operating at atmospheric pressure, i.e., 1 atm.
Claim 8: As shown by Ackerman’s drawing, the first end of the furnace tube is flanged such that its outer diameter exceeds that of the furnace tube at a middle section. This flange mates with the backing plate.
Claim 10: Ackerman’s furnace tube is oriented horizontally, whereby the fluid inlet is disposed at the first end and the fluid outlet is disposed at the second end.
Claim 32: The material selected to compose the barrier layer is a matter of intended use, as the operator is capable of providing the necessary gases to yield the claimed materials.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Ackerman in view of Nishitani and Reynolds, and in further view of Koo et al., US 2014/0356547, and Arai et al., US 4,543,472.
The cited prior art is silent regarding the matter of biasing the metal furnace tube. Koo, though, attests that it is advantageous to bias the walls of a processing chamber so as to attract ions for purposes of cleaning [0010]. Deposits necessarily accumulate on the walls of the chamber over time, and biasing said walls to initiate ionic collisions will facilitate the removal of the deposits [0028]. For at least these reasons, it would have been obvious to the skilled artisan to hold the furnace tube at a given potential during a cleaning procedure.
Separately, regarding the stipulation of electrical isolation between the furnace tube and furnace cabinet, Arai discloses a processing space (1) situated within a furnace tube (11) which, in turn, is situated within a cabinet (4, 6) (3, 4-42; Fig. 6). In order to isolate the cabinet and tube, Arai provides insulators (25) at each electrical coupling point (26) (3, 55-64). It would have been obvious to electrically insulate these two bodies at vulnerable locations to prevent arcing and maintain their respective electrical potentials.
Claim 33 is rejected under 35 U.S.C. 103 as being unpatentable over Ackerman in view of Nishitani and Reynolds, and in further view of Yamabe et al., US 5,259,883.
Although Ackerman situates a heater (7) about the circumference of the furnace tube (1), the reference is silent regarding the claimed feature of a “thermally conductive material interposed between the heater and the metal furnace tube.” Remedying the omission is Yamabe, who, like Ackerman, discloses a metal furnace tube (11) configured to retain a plurality of substrates (15) (Fig. 1). In order to regulate the processing temperature, Yamabe disposes a heater (18) about the circumference of the furnace tube yet additionally inserts a silicon carbide wrap (17) between the heater and tube in order to uniformly distribute the radiant heat (3, 45-51). As silicon carbide exhibits high thermal conductivity, over 200 W/m*K, the examiner understands Yamabe’s wrap (17) to read upon the claimed “thermally conductive material” of claim 33. It would have been obvious to interpose a silicon carbide material between Ackerman’s heater and furnace tube to better regulate the distribution of heat.
Claim 34 is rejected under 35 U.S.C. 103 as being unpatentable over Ackerman in view of Nishitani and Reynolds, and in further view of Arai.
Ackerman does not teach a cooling conduit. Arai, in supplementation, provides a horizontal reaction tube outfitted with heaters (10) (3, 5-40). In order to quickly reduce the operating temperature of the reactor, Arai also furnishes the apparatus with conduits (W) at the inlet and outlet, respectively, for circulating a coolant (3, 65ff; Fig. 1). It would have been obvious to integrate similarly situated cooling conduits within Ackerman’s apparatus to achieve the predictable result of responsive temperature control.
Conclusion
The following prior art is made of record as being pertinent to Applicant’s disclosure, yet is not formally relied upon: Kang et al., US 2012/0269498. Kang discloses a horizontal furnace comprising first and second base plates (120), whereby a fluid inlet (520) couples to a first end and a fluid outlet (620) couples to a second end (Fig. 1).
THIS ACTION IS MADE FINAL. 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 extension fee 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to NATHAN K FORD whose telephone number is (571)270-1880. The examiner can normally be reached on 11-7:30 PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Parviz Hassanzadeh, can be reached at 571 272 1435. The fax phone number for the organization where this application or proceeding is assigned is 571 273 8300.
/N. K. F./
Examiner, Art Unit 1716
/KARLA A MOORE/ Primary Examiner, Art Unit 1716
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