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 .
Specification
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
The following title is suggested:
Nitrogen-doped polycrystalline SiC molded body having an average grain size of 5 mm or less and method for producing the same by performing CVD on a heated base material
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 3-4 and 6-7 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 pre-AIA the applicant regards as the invention.
Claims 3 and 6 depend from claims 1 and 2, respectively, and recite, inter alia, the step of forming “a polycrystalline SiC film.” However, it is unclear whether the polycrystalline SiC film is the same as or different from the polycrystalline Si molded body recited in claim 1. For examination purposes it is assumed that the polycrystalline SiC film formed in the method of claims 3 and 6 is, in fact, the polycrystalline SiC molded body recited in claim 1. Dependent claims 4 and 7 are similarly rejected due to their dependence on claims 3 and 6, respectively.
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 1-2 is/are rejected under 35 U.S.C. 103 as being unpatentable over a publication to Noh, et al. entitled “A study of electrical properties and microstructure of nitrogen-doped poly-SiC films deposited by LPCVD,” Sensors and Actuators A, Vol. 136, pp. 613-17 (2007) (“Noh”) in view of Japanese Patent No. JP 4595153 B2 (“the JP ‘153 patent”).
Regarding claim 1, Noh teaches a polycrystalline SiC molded body (see the Abstract, Figs. 1-6, Table 1, and the entire reference, including specifically Figs. 1 & 3-4 which teach a polycrystalline SiC molded body) having
an average crystal grain size of 5 mm or less (see Figs. 3-4 and the second full paragraph of the Results and discussion section at p. 615-16 which teach that the average grain size is 165 to 200 nm);
a nitrogen concentration (see Fig. 2, Table 1, and the Experimental and Results sections at pp. 614-16 which teach that the polycrystalline SiC body is doped with nitrogen in an amount determined by the dopant gas flow rate in order to obtain a predetermined resistivity).
Noh does not explicitly teach that the SiC molded body has a nitrogen concentration of 2.7×1019 to 5.4×1020 (atoms/cm3). However, as noted supra, in Fig. 2, Table 1, and the Experimental and Results sections at pp. 614-16 Noh teaches that the nitrogen concentration and, hence, the resistivity is directly proportional to the NH3 gas flow with a higher flow rate producing a higher nitrogen concentration and, consequently, a lower resistivity. In the first full paragraph on p. 615 Noh specifically teaches that it is known in the art that the limiting resistivity also depends on the type of dopant used. Although Noh is silent regarding the exact nitrogen concentration that is obtained from a 20 to 100 sccm flow rate of NH3, since the nitrogen flow rate is a result-effective variable, it therefore would have been within the capabilities of a person of ordinary skill in the art prior to the effective filing date of the invention to utilize routine experimentation to optimize the type of nitrogen-containing precursor as well as its flow rate to obtain the desired nitrogen concentration within the polycrystalline SiC body, including within the claimed range of 2.7×1019 to 5.4×1020 atoms/cm3, that is necessary for a particular application. In this case the specific motivation for optimizing the nitrogen concentration would be to obtain the resistivity required for a given application.
Noh also does not explicitly teach that the polycrystalline SiC molded body has a product of carrier density × Hall mobility of 4.0×1020 to 6.0×1021 (atoms/cmVsec). However, in Fig. 2 and the first full paragraph on p. 615 Noh teaches that the resistivity decreases to 0.036 W-cm as the NH3 flow rate is increased to 100 sccm. Then in ¶¶[0008]-[0023] as well as the Example in ¶¶[0024]-[0026] the JP ‘153 patent teaches an analogous method of producing nitrogen-doped polycrystalline SiC by chemical vapor deposition (CVD). In ¶¶[0020]-[0021] the JP ‘153 patent teaches that nitrogen (N2) is preferably used as the dopant gas in a concentration of up to 50 mol. % while ¶¶[0009]-[0011] further teach that this produces a resistivity as low as 0.01 W-cm. Since the carrier density is proportional to the nitrogen concentration (i.e., the dopant density) a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of the JP ‘153 patent and would be motivated to utilize N2 as the dopant gas in the method of Noh and would utilize routine experimentation to optimize the N2 flow rate to obtain an even lower resistivity on the order of 0.01 W-cm which falls within the range of 0.020 W-cm or less as disclosed in Table 1 of the instant application. Moreover, since the nitrogen-doped polycrystalline SiC molded body taught by the combination of Noh and the JP ‘153 patent are produced by the same method (i.e., by CVD) and possesses the same average grain size and nitrogen concentration, it must necessarily possess the same properties. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See also MPEP 2112.01.
Regarding claim 2, Noh does not teach that the polycrystalline SiC molded body has a volume resistivity of 0.020 W-cm or less. However, as noted supra with respect to the rejection of claim 1, in ¶¶[0020]-[0021] the JP ‘153 patent teaches that nitrogen (N2) is preferably used as the dopant gas in a concentration of up to 50 mol. % while ¶¶[0009]-[0011] further teach that this produces a resistivity as low as 0.01 W-cm. Since the carrier density is proportional to the nitrogen concentration (i.e., the dopant density) a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of the JP ‘153 patent and would be motivated to utilize N2 as the dopant gas in the method of Noh and would utilize routine experimentation to optimize the N2 flow rate to obtain an even lower resistivity on the order of 0.01 W-cm
Claims 3-4 and 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Noh in view of the JP ‘153 patent and further in view of U.S. Patent Appl. Publ. No. 2002/0037801 to Sugihara, et al. (“Sugihara”).
Regarding claim 3, Noh teaches a method for producing the polycrystalline SiC molded body according to claim 1 (see Figs. 1 & 3-4 and the Experimental section at pp. 614-15), comprising the steps of:
placing a base material in a CVD reaction furnace (see the Experimental section at pp. 614-15 which teaches that a Si(100) wafer with a thermally grown silicon dioxide layer is placed in a CVD furnace);
heating the base material (see the Experimental section at pp. 614-15 which teaches heating the substrate to 900 °C); and
forming a polycrystalline SiC film on the heated base material by a CVD method by introducing a mixed gas containing a raw material gas and a nitrogen-containing gas into the CVD reacting furnace (see the Experimental section at pp. 614-15 which teaches feeding raw material gases including SiH2Cl2, C2H2, and NH3 into the CVD furnace to deposit a polycrystalline SiC film);
wherein the forming step is performed under a condition that there is an arrival time t, which represents a time from when the mixed gas is introduced into the CVD reaction furnace to when the mixed gas reaches the base material (see the Experimental section at pp. 614-15 which teaches that the precursor gases enter the CVD chamber from the load end during film growth which necessarily means that there is an arrival time t between when the gas enters the CVD chamber and reaches the silicon substrate).
Noh and the JP ‘153 patent do not teach that the arrival time t is 1.6 to 6.7 seconds. However, at p. 614 the Experimental section teaches that the reaction chamber is a conventional horizontal furnace having a length of 2007 mm and an inner diameter of 225 mm which necessarily means that it takes a predetermined amount of time for the precursor gases to travel from the gas inlet to the substrate which necessarily is influenced by, inter alia, the chamber pressure, the precursor gas concentration, and the gas flow rates. Then in Fig. 1, ¶¶[0011]-[0012], and ¶¶[0016]-[0025] as well as elsewhere throughout the entire reference Sugihara teaches an analogous system and method for the deposition of a doped SiC layer by CVD from the desired precursor gases. In ¶[0012], ¶[0020], and ¶[0023] Sugihara specifically teaches that for a given chamber geometry and volume there is an optimal raw material gas retardation time which is calculated based on the effective reaction volume in the reaction chamber, the raw material gas flow rate, and the reaction temperature. For the specific chamber geometry shown in Fig. 1 of Sugihara the retardation time is preferably controlled to within the range of 7 to 110 seconds. If the retardation time is less than 7 s the specific gravity of SiC is decreased and it is prone to absorbing impurity gases which cause the oxidation and corrosion resistance to decrease, but if the retardation time is greater than 110 seconds, then the deposition rate is reduced. Thus, the teachings of Sugihara show that there is an optimal retardation time for a given system geometry. Moreover, the retardation time of Sugihara is analogous to the arrival time t of the instant application since they both relate to how long it takes for gas molecules to reach and then stay in the vicinity of the substrate before being evacuated from the chamber. It therefore would have been within the capabilities of a person of ordinary skill in the art prior to the effective filing date of the invention to utilize routine experimentation to determine the optimal arrival time t for precursors gases in the system and method for SiC growth as taught by Noh and the JP ‘153 patent by adjusting the precursor gas flow rates, the system pressure, the substrate temperature, and the placement of the substrate within the reaction chamber to arrive at an optimal value which falls within the claimed range of 1.6 to 6.7 s. “Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CPA 1955). See also MPEP 2144.05(II)(A).
Regarding claim 4, Noh and the JP ‘153 patent do not teach that the forming step is performed under such a condition that a film forming speed becomes 400 to 1300 mm/hr. However, since the growth rate is determined by, inter alia, the flow rate of the precursor gases and the chamber pressure the desired growth rate may be established by, for example, increasing or decreasing the precursor flow rate(s) such that a larger or smaller amount of precursor arrives at the substrate and is deposited as a polycrystalline SiC layer per unit time. This is exemplified by, for example, at least Fig. 1 and ¶¶[0016]-[0025] of Sugihara which teaches an analogous system and method for the deposition of a doped SiC layer by CVD from the desired precursor gases. In ¶[0022] Sugihara teaches that a dense high purity nitrogen-doped SiC layer may be formed at a deposition rate of up to 400 mm/h which touches the claimed range. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Sugihara and would be motivated to increase the deposition rate in the method of Noh and the JP ‘153 patent up to at least 400 mm/hr in order to deposit a dense high purity nitrogen doped polycrystalline SiC film with increased throughput.
Regarding claim 6, Noh teaches a method for producing the polycrystalline SiC molded body according to claim 1 (see Figs. 1 & 3-4 and the Experimental section at pp. 614-15), comprising the steps of:
placing a base material in a CVD reaction furnace (see the Experimental section at pp. 614-15 which teaches that a Si(100) wafer with a thermally grown silicon dioxide layer is placed in a CVD furnace);
heating the base material (see the Experimental section at pp. 614-15 which teaches heating the substrate to 900 °C); and
forming a polycrystalline SiC film on the heated base material by a CVD method by introducing a mixed gas containing a raw material gas and a nitrogen-containing gas into the CVD reacting furnace (see the Experimental section at pp. 614-15 which teaches feeding raw material gases including SiH2Cl2, C2H2, and NH3 into the CVD furnace to deposit a polycrystalline SiC film);
wherein the forming step is performed under a condition that there is an arrival time t, which represents a time from when the mixed gas is introduced into the CVD reaction furnace to when the mixed gas reaches the base material (see the Experimental section at pp. 614-15 which teaches that the precursor gases enter the CVD chamber from the load end during film growth which necessarily means that there is an arrival time t between when the gas enters the CVD chamber and reaches the silicon substrate).
Noh and the JP ‘153 patent do not teach that the arrival time t is 1.6 to 6.7 seconds. However, at p. 614 the Experimental section teaches that the reaction chamber is a conventional horizontal furnace having a length of 2007 mm and an inner diameter of 225 mm which necessarily means that it takes a predetermined amount of time for the precursor gases to travel from the gas inlet to the substrate which necessarily is influenced by, inter alia, the chamber pressure, the precursor gas concentration, and the gas flow rates. Then in Fig. 1, ¶¶[0011]-[0012], and ¶¶[0016]-[0025] as well as elsewhere throughout the entire reference Sugihara teaches an analogous system and method for the deposition of a doped SiC layer by CVD from the desired precursor gases. In ¶[0012], ¶[0020], and ¶[0023] Sugihara specifically teaches that for a given chamber geometry and volume there is an optimal raw material gas retardation time which is calculated based on the effective reaction volume in the reaction chamber, the raw material gas flow rate, and the reaction temperature. For the specific chamber geometry shown in Fig. 1 of Sugihara the retardation time is preferably controlled to within the range of 7 to 110 seconds. If the retardation time is less than 7 s the specific gravity of SiC is decreased and it is prone to absorbing impurity gases which cause the oxidation and corrosion resistance to decrease, but if the retardation time is greater than 110 seconds, then the deposition rate is reduced. Thus, the teachings of Sugihara show that there is an optimal retardation time for a given system geometry. Moreover, the retardation time of Sugihara is analogous to the arrival time t of the instant application since they both relate to how long it takes for gas molecules to reach and then stay in the vicinity of the substrate before being evacuated from the chamber. It therefore would have been within the capabilities of a person of ordinary skill in the art prior to the effective filing date of the invention to utilize routine experimentation to determine the optimal arrival time t for precursors gases in the system and method for SiC growth as taught by Noh and the JP ‘153 patent by adjusting the precursor gas flow rates, the system pressure, the substrate temperature, and the placement of the substrate within the reaction chamber to arrive at an optimal value which falls within the claimed range of 1.6 to 6.7 s. “Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CPA 1955). See also MPEP 2144.05(II)(A).
Regarding claim 7, Noh and the JP ‘153 patent do not teach that the forming step is performed under such a condition that a film forming speed becomes 400 to 1300 mm/hr. However, since the growth rate is determined by, inter alia, the flow rate of the precursor gases and the chamber pressure the desired growth rate may be established by, for example, increasing or decreasing the precursor flow rate(s) such that a larger or smaller amount of precursor arrives at the substrate and is deposited as a polycrystalline SiC layer per unit time. This is exemplified by, for example, at least Fig. 1 and ¶¶[0016]-[0025] of Sugihara which teaches an analogous system and method for the deposition of a doped SiC layer by CVD from the desired precursor gases. In ¶[0022] Sugihara teaches that a dense high purity nitrogen-doped SiC layer may be formed at a deposition rate of up to 400 mm/h which touches the claimed range. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Sugihara and would be motivated to increase the deposition rate in the method of Noh and the JP ‘153 patent up to at least 400 mm/hr in order to deposit a dense high purity nitrogen doped polycrystalline SiC film with increased throughput.
Response to Arguments
Applicant's arguments filed December 17, 2025, have been fully considered and are persuasive with respect to the argument relating to close enough ranges, but they are not persuasive with respect to the argument relating to the optimization of ranges.
Applicant’s proposed amendment to the title has been reviewed, but it remains overly generic as it provides no indication as to the nature of the SiC molded body or the method of its manufacture as recited in the pending claims. A proposed replacement title has been suggested by the Examiner.
Applicant argues against the 35 U.S.C. 112(b) rejection of claims 3-4 and 6-7 by contending that the polycrystalline SiC is referred to as a “film” when present on a substrate and as a “molded body” when the substrate is absent. See applicants’ 12/17/25 reply, p. 6. Applicants’ argument is noted, but appears to affirm the 35 U.S.C. 112(b) rejection of the claims as it is unclear how the SiC molded body is formed if the method in claims 3 and 6 only recite forming a SiC film. Since only a SiC film is formed on the base material and the base material has not been removed, the method recited in claims 3 and 6 does not, in fact, produce the SiC molded body of claim 1.
Applicant initially argues against the 35 U.S.C. 103 rejection of claim 1 by contending that since the NH3 source in Noh contains 1% NH3 in H2, nitrogen is not incorporated into the SiC to the same extent as in the present invention. Id. at p. 8. This argument is found persuasive and, consequently, the Examiner’s assertion that Noh discloses a nitrogen concentration that is sufficiently close to the claimed range has been withdrawn. However, as further discussed infra, applicants have not provided sufficient evidence to show that an ordinary artisan could not or would not obtain the recited nitrogen concentration through routine experimentation in order to obtain the desired electrical properties.
Applicants then argue against the reliance on the JP ‘153 patent by contending that when nitrogen is added in an amount which exceeds the solid solution limit, a compound different from SiC is generated, making it impossible to exert a function required as a polycrystalline SiC molded body and that there is no motivation to modify the teachings of Noh in view of the JP ’153 patent and have any reasonable expectation of success. Id. at pp. 8-9. Applicants’ arguments are noted, but are unpersuasive for at least two main reasons. First, the Examiner’s position is not that nitrogen is added to make a solid solution, but instead it is based on the premise that the nitrogen source material used as well as its flow rate may be optimized through routine experimentation in order to obtain both the desired dopant concentration and electronic properties. In Fig. 2, Table 1, and the Experimental and Results sections at pp. 614-16 Noh specifically teaches that the nitrogen concentration and, hence, the resistivity is directly proportional to the NH3 gas flow with a higher flow rate producing a higher nitrogen concentration with the first full paragraph on p. 615 of Noh specifically teaching that the limiting resistivity also depends on the type of dopant used. Then the JP ‘153 patent further teaches that the use of N2 as a dopant gas during CVD growth of polycrystalline SiC films produces still higher nitrogen concentrations and an even lower resistivity on the order of 0.01 W-cm which falls within the range of 0.020 W-cm or less as disclosed in Table 1 of the instant application. Thus, the combined teachings of Noh and the JP ‘153 patent show that the desired nitrogen concentration and, hence, the electronic properties of the resulting polycrystalline SiC film may be obtained through routine experimentation. Second, it is pointed out that applicants have not provided any evidence showing that the recited nitrogen concentration range is critical or produces unexpected results. Instead, applicants merely present a general allegation that the present invention produces unexpected results by making it possible to “solid-dissolve nitrogen while nitrogen is contained in such a concentration.” In this case, applicants position appears (i) to be based on arguments of counsel rather than factually supported objective evidence and (ii) to be based on features which are not claimed since there is nothing in the claims which relates to “solid-dissolving nitrogen.” It has previously been held that the arguments of counsel cannot take the place of factually supported objective evidence. See, e.g., In re Huang, 100 F.3d 135, 139-40, 40 USPQ2d 1685, 1689 (Fed. Cir. 1996); In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984). See also MPEP 2145.
Applicants then argue against the rejection of claim 3 by contending that since there is a significant difference between the retardation time of Sugihara and the arrival time t of the instant application an ordinary artisan would not have any motivation to modify the teachings of Noh and the JP ‘153 patent in view of Sugihara and have any expectation of success at arriving at the present invention. Id. at pp. 11-12. This argument also is found unpersuasive since it is again based on arguments of counsel rather than factually supported objective evidence. The instant application defines the arrival time t as the time from which the mixed gas is introduced into the CVD reaction furnace to when it reaches the base material. The value of t is necessarily influenced by factors such as the flow rate (i.e., the speed) of the precursor gases, the chamber pressure (i.e., number of atomic collisions in the gas phase), and the temperature. As explained in ¶[0008] of Sugihara, experiments were carried out to investigate the relationship among the reaction conditions, such as the ratio of concentration of gases introduced into the reactor and the residence time of the gases on the materials properties of the resulting SiC film. In particular, in ¶[0012] Sugihara defines the raw material gas retardation time in seconds using the following expression:
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Since the retardation time is based on a ratio of the total volume of the reaction chamber to the raw material gas flow rate it therefore provides a measure of how quickly the raw material gas fills or passes through the reaction chamber. For a given reaction volume the above expression means that a higher (lower) gas flow rate produces a smaller (larger) retardation time as the raw material gas passes through the chamber more quickly. Similarly, for a given gas flow rate a larger (smaller) reaction chamber results in a larger (smaller) retardation time as it takes longer for the gas to pass through a larger reaction chamber and vice versa. Thus, the retardation time as taught by Sugihara is analogous to the arrival time as recited in claims 3 and 6 of the instant application because both relate to how long it takes precursor gas(es) to travel a specific distance within a reaction chamber. It therefore is the Examiner’s position that an ordinary artisan would look to the teachings of Sugihara and would be motivated to utilize routine experimentation to determine the optimal gas flow rate(s), pressure, and temperature for a given system volume and geometry which will, in turn, necessarily yield an optimal arrival time t that falls within the claimed range of 1.6 to 6.7 seconds. Moreover, applicants have not provided evidence on the record which tends to show that a value of t = 1.6 to 6.7 s is critical and yields unexpected results in order to rebut a prima facie determination of obviousness based on optimization of ranges.
Conclusion
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 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KENNETH A BRATLAND JR whose telephone number is (571)270-1604. The examiner can normally be reached Monday- Friday, 7:30 am to 4:30 pm EST.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714