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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-6 in the reply filed on August 5, 2026, is acknowledged.
Claims 7-17 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on August 5, 2026.
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:
Silicon carbide growth system comprising a crucible, a seed holder, an off-axis seed, and an induction coil with an angle between a normal direction of the induction coil and a growth direction of the off-axis seed
Claim Interpretation
A “normal direction of the induction coil” as recited in claim 1 is interpreted in view of at least Figs. 2-3 and ¶[0023] of the published application as the direction (N) that is perpendicular to the thread of the induction coil (122).
It is noted that claim 1 is an apparatus claim and recites that “the seed holding surface is configured to hold an off-axis seed.” In this regard, the term “configured to” is interpreted to mean that the seed holding surface is capable of holding an off-axis seed and the claim language does not specifically require that an off-axis seed is an actual component of the claimed apparatus.
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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1 and 4-6 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Appl. Publ. No. 2014/0196659 to Shin, et al. (hereinafter “Shin”) in view of Chinese Patent Appl. Publ. No. CN 217418863 U to Liu, et al. (“Liu”).
Regarding claim 1, Shin teaches a silicon carbide crystal growth system (see the Abstract, Figs. 1-2, and entire reference which teach an embodiment of a SiC sublimation growth system), comprising:
a crucible comprising a crucible body and a crucible cover, wherein the crucible body has an internal space for accommodating a raw material, the crucible cover covers the crucible body (see Fig. 1 and ¶¶[0023]-[0052] which teach a crucible (100) having a crucible cover thereupon with an internal space that accommodates a raw material (130));
a heating device comprising an induction coil and a quartz tube, wherein the induction coil is spirally wound on an outer wall of the quartz tube, the crucible is disposed in the quartz tube, and the crucible is disposed coaxially with the quartz tube (see Fig. 1 and ¶¶[0023]-[0052] which teach that the crucible (100) is disposed within and coaxially aligned with a quartz pipe (400) with an induction coil (500) being spirally wound around the quartz pipe (400)); and
a seed holder disposed on the crucible cover and comprising a seed holding surface, wherein the seed holding surface is configured to hold an off-axis seed and is perpendicular to a central axis of the crucible (see Fig. 1 and ¶¶[0023]-[0052] which teach a seed holder (160) disposed underneath the cover which has a seed holding surface that is configured to (i.e., is capable of) holding an off-axis seed (170); moreover the horizontal planar surface of the seed holder (160) is perpendicular to a central axis of the crucible (100)), and
a silicon carbide crystal grows from a growth surface of the off-axis seed along isotherms of a thermal field provided by the induction coil, thereby obtaining a silicon carbide boule (see Fig. 7 and ¶¶[0059]-[0060] as well as elsewhere throughout the entire reference which teach that the sublimation system is configured for the growth of a SiC single crystal (190) vertically downward from the horizontal growth plane of the seed crystal (170) along isotherms of a thermal field which is necessarily produced by the induction coil (500)).
Shin does not teach that an angle between a normal direction of the induction coil and a growth direction of an off-axis seed that is provided on the seed holding surface is between 0 degrees and 10 degrees. However, at pp. 1-2 Liu teaches that traditional SiC single crystal sublimation surfaces which use an induction heating coil utilize a copper pipe that is bent to form a spiral rising pattern that has an inclined angle relative to the heated workpiece which therefore causes each turn of the coil to be asymmetric relative to the vertical axis of the system. One potential solution to this is to produce an induction coil structure in which each coil is horizontal such that a normal to the plane of each winding is parallel to a central axis of the sublimation growth system. This is specifically exemplified by at least Figs. 1-3 and Embodiment 1 at pp. 4-5 which teaches an embodiment in which a stepped induction coil (3) surrounds the graphite crucible (4) such that a normal to each turn of the coil (3) makes an angle of 0° relative to a central axis of the crucible (4). Thus, a PHOSITA prior to the effective filing date of the invention would utilize the stepped induction coil (3) of Liu as the induction coil in the sublimation growth system of Shin such that there is an angle of 0° between a normal to the surface of each individual winding and a central axis of the sublimation growth system with the motivation for doing so being to produce a more symmetric temperature profile which is parallel to the axis of the crucible in order to grow a more uniform SiC single crystal ingot. In this case, the use of a SiC(0001) seed crystal having an off-axis of greater than 0, but less than or equal to 10° in the apparatus of Shin and Liu would then produce an angle of between 0 and 10° between the off-axis of the SiC seed crystal and a normal to each coil of the indication coil as claimed.
Regarding claim 4, Shin and Liu teach that the number of turns of the induction coil is 6 turns to 13 turns (See Fig. 1 and ¶¶[0059]-[0060] as well as elsewhere throughout the entirety of Shin which show that the induction coil (500) includes 8 pairs of coils which therefore means that there are 8 turns which falls within the claimed range. See also Figs. 1-2 and Embodiment 1 at pp. 4-5 of Liu which teach that the induction coil (3) includes 10 turns which also falls within the claimed range. Moreover, since the number of turns in the induction coil plays a role in determining the strength, shape, and size of the resulting electric and magnetic fields that heat the crucible (100) it is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). It therefore would have been within the capabilities of a PHOSITA prior to the effective filing date of the invention to utilize routine experimentation to determine the optimal number of turns in the induction coil, including within the claimed range of 6 to 13 turns, that is necessary to produce the desired heating effect.).
Regarding claim 5, Shin teaches that an angle between a line perpendicular to a connection line of two ends of a cross section of a surface of the silicon carbide boule away from the off-axis seed and a normal direction of the off-axis seed is substantially equal to an angle between the normal direction of the induction coil and a gravity direction (See Fig. 7 and ¶¶[0059]-[0060] as well as elsewhere throughout the entire reference which show that a connection line across the two ends of the SiC ingot (190) produces a horizontal line whose normal is parallel to the vertical axis of the sublimation system which therefore produces an angle with the normal direction to the off-axis seed that is equal to the off-axis angle. Moreover, since the normal to the induction coils of Liu is parallel to the direction of gravity, the angle formed therebetween is zero. In this case when the of-axis angle of the SiC seed crystal is a small amount such as 0.5°, this may be broadly considered as substantially equal to 0° since the difference is so small that it would be reasonably expected to produce the same results during growth of a SiC single crystal.).
Regarding claim 6, Shin teaches a thermal insulation material disposed outside the crucible body and the crucible cover (see Fig. 1 and ¶¶[0023]-[0052] which teach that thermal insulation (200) is disposed outside the crucible (100)).
Claim 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shin in view of Liu and further in view of U.S. Patent Appl. Publ. No. 2013/0161646 to Nishiguchi, et al. (“Nishiguchi”).
Regarding claim 2, Shin and Liu do not teach that an axial length of the induction coil spirally wound on the quartz tube is 50 centimeters to 110 centimeters. However, since the size of the crucible and/or quartz tube utilized for SiC sublimation growth determines the size of the induction coil needed to efficiently and uniformly heat the entire sublimation growth system to the desired temperature, a PHOSITA would be motivated to utilize an induction coil having an axial length that is at least the same as or slightly greater than the vertical height of the crucible. This is specifically shown in Fig. 1 of Shin which shows that the vertical height of the induction coil (500) extends from a top of the crucible (100) to just below the bottom insulation (200). In this regard in at least Fig. 6 and the Examples at ¶¶[0122]-[0126] Nishiguchi discloses an analogous embodiment of a sublimation growth system in which a typical sublimation growth crucible (11) has a height of 100 cm. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to utilize routine experimentation to determine the optimal axial height of the induction coil, including within the claimed range of 50 to 110 cm, with the motivation for doing so being to efficiently and uniformly heat a sublimation growth crucible having a typical height of approximately 100 cm.
Claim 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shin in view of Liu and further in view of a publication to Juan Su, et al. entitled “Numerical design of induction heating in the PVT growth of SiC crystal,” Journal of Crystal Growth, Vol. 401, pp. 128-132 (2014) (“Su”).
Regarding claim 3, Shin and Liu do not teach that a distance between centers of two adjacent turns in the induction coil is 30 millimeters to 100 millimeters. However, in the Abstract and Introduction section at p. 128 Su teaches that the dimensions, axial position, and operating parameters of the induction heating coil utilized in a SiC sublimation growth system influence growth parameters such as the maximum temperature during growth, the temperature distribution, and the growth rate. In Figs. 2-9 Su specifically investigates the influence of the coil radius and electrical frequency on the temperature distribution and the resulting average growth rate of SiC. In Fig. 1 and Tables 1-2 Su specifically discloses the experimental parameters used, including the dimensions and spacing of the induction coil, the latter of which is 27.8 mm and is sufficiently close to the claimed lower limit of 30 mm that it would be reasonably expected to yield the same properties. Since the spacing of individual coils and, consequently, the density of the coil windings determines the maximum temperature and the resulting temperature distribution within the sublimation growth crucible it is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). It therefore would have been within the capabilities of a PHOSITA prior to the effective filing date of the invention to start with a spacing of 27.8 mm as taught by Su and then utilize routine experimentation to determine the optimal coil spacing, including within the claimed range of 30 to 100 mm, necessary to produce the desired temperature profile during sublimation growth of a SiC single crystal ingot.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. In at least Fig. 2 and ¶[0038]-[0040] U.S. Patent Appl. Publ. No. 2008/0008641 to Leonard, et al. teaches an embodiment of a SiC seed crystal having an off-axis of between 0.5 and 12° for sublimation growth of a SiC ingot.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714
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