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 .
Status of the Claims
Amendment filed June 16, 2026 is acknowledged. New Claims 11-14 have been added. Claims 1 and 7-8 have been amended. Claims 1, 3, 5-8 and 11-14 are pending.
Action on merits of claims 1, 3, 5-8 and 11-14 follows.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claim 11 is rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
There does not appear to be a written description of the claim limitation “wherein the process of activate the first well ions in the first implantation region avoids damage to a surface of the silicon carbide substrate at the channel caused by direct multiple aluminum ion implantations” (new claim 11) (emphasis added) in the application as filed.
The manufacturing method is carried out with only one aluminum implantation. (See FIG. 2B.
Therefore, claim 11 contains new matter.
Applicant must cancel the un-support new matters in response to the Office Action.
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.
Claim 12 is 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 12 recites the limitation "The manufacturing method according to claim 1, wherein in the formed well region, the first implantation region extends laterally wider than the second implantation region.
However, there are at least two well regions being formed in claim 1.
Which well that “in the formed well region” is directed to?
Therefore, claim 12 is indefinite.
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.
Claims 13-14 are 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.
New Claim 13 recites: the manufacturing method according to claim 1, wherein an implantation energy of the aluminum ions used to form the second implantation region is higher than an implantation energy of the boron ions or boron fluoride ions used to form the first implantation region.
The limitation of claim 13 has already been recited in claim 1.
Therefore, claim 13 fails to further limit claim 1.
New Claim 14 recites: the manufacturing method according to claim 1, wherein the ion implantation steps for forming the first implantation region, the second implantation region, and the source region are performed using a (sic) same patterned mask layer, so that a photoetching frequency is effectively reduced.
The limitation: “so that a photoetching frequency is effectively reduced” is a direct result of the implantation steps being performed using a same patterned mask layer of claim 1.
Therefore, claim 14 fails to further limit claim 1.
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.
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.
Claim 1, 3, 5-8 and 11-14 are rejected under 35 U.S.C. 103 as being unpatentable over MIWA et al. (US. Pub. No. 2022/0336219) in view of HERMAN (US. Patent No. 6,346,726) both of record.
With respect to claim 1, MIWA teaches a manufacturing method of a metal oxide semiconductor field effect transistor (MOSFET) device, substantially as claimed including:
providing a silicon carbide substrate (10), forming a patterned mask layer (90c) for defining a well region on a front of the silicon carbide substrate and using the patterned mask layer (90c) as a mask, and implanting first well ions of a first conductive type into a surface layer on the front of the silicon carbide substrate (10) to form a first implantation region (31), wherein the first well ions comprise P-type ions;
using a patterned mask layer (90a) as the mask, implanting second well ions of the first conductive type into the silicon carbide substrate below the first implantation region (31) to form a second implantation region (30), wherein the second well ions comprise aluminum ions, and an implantation energy thereof is higher than an implantation energy of the first well ions, such that a junction depth of the second implantation region (30) is greater than a junction depth of the first implantation region (31);
using the patterned mask layer (90a) as the mask, implanting source ions of a second conductive type into a surface layer of the first implantation region (31) to form a source region (40);
removing the patterned mask layer, and annealing the silicon carbide substrate by a high-temperature annealing process to activate the first well ions in the first implantation region (31) so that the first implantation region (31) is longitudinally connected to the second implantation region (30) and horizontally extends to a required width to provide a required channel width subsequently, so as to form a required well region, wherein the high-temperature annealing process is performed at a temperature ranging from 1500°C to 1900°C; and
forming a gate oxide layer (50) and a gate (60) which are stacked in sequence on the front of the silicon carbide substrate, and using a region where the first implantation region (31) is in contact with the gate oxide layer (50) as a channel of the MOSFET device,
wherein in the process of activate the first well ions in the first implantation region (31), a diffusion coefficient of the source ions in the source region (40) is less than a diffusion coefficient of the first well ions in the first implantation region (30), the channel of the MOSFET device is formed by diffusion of the first implantation region (30),
wherein the ion implantation for the first implantation region (30), the second implantation region (36), and the source region (33) is performed using a same mask layer (90). (See Figs. 3-7).
Thus, MIWA is shown to teach all the features of the claim with the exception of explicitly disclosing the first well ions comprise boron ions or boron fluoride ions; and a diffusion coefficient of the second well ions is less than a diffusion coefficient of the first well ions.
However, HERMAN teaches a manufacturing method of a metal oxide semiconductor field effect transistor (MOSFET) device including:
providing a substrate (52), forming a patterned mask layer (61) for defining a well region on a front of the substrate and using the patterned mask layer (61) as a mask, and implanting first well ions of a first conductive type into a surface layer on the front of the substrate to form a first implantation region (80), wherein the first well ions comprise boron ions or boron fluoride ions;
using the patterned mask layer (61) as the mask, implanting second well ions of the first conductive type into the substrate below the first implantation region (80) to form a second implantation region (85), wherein the second well ions comprises the first type ions, and an implantation energy thereof (150 keV) is higher than an implantation energy (80 keV) of the first well ions, such that a junction depth of the second implantation region (85) is greater than a junction depth of the first implantation region (80);
using the patterned mask layer (61) as the mask, implanting source ions of a second conductive type into a surface layer of the first implantation region (80) to form a source region (81);
annealing the substrate by a high-temperature annealing process to activate the first well ions in the first implantation region (80) so that the first implantation region (80) is longitudinally connected to the second implantation region (85) and horizontally extends to a required width to provide a required channel width subsequently, so as to form a required well region, wherein the annealing process is performed at a high temperature; and
wherein in the process of activate the first well ions in the first implantation region (80), a diffusion of the source ions in the source region (81) is less than a diffusion coefficient of the first well ions in the first implantation region (80), the channel of the MOSFET device is formed by diffusion of the first implantation region (80),
wherein the ion implantation for the first implantation region (80), the second implantation region (85), and the source region (81) is performed using a same mask layer (61). (See Figs. 6-7).
Therefore, it would have been obvious to one having ordinary skill in the art at the time of invention was made to form the first implantation region of MIWA utilizing the first well ions comprising boron ions as taught by HERMAN so that upon the thermal activation the channel is formed.
Regarding the diffusion coefficients, in view of HERMAN, the first well ions comprises boron, thus, the limitation: the diffusion coefficient of the second well ions (aluminum) in the second implantation region of MIWA, and a diffusion coefficient of the source ions in the source region is less than a diffusion coefficient of the first well ions (boron), in view of HERMAN, in the first implantation region, is met.
Moreover, it has been held to be within the general skill of a worker in the art to select a known material, boron ions of aluminum ions, on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416., 125 USPQ 416.
With respect to claim 3, after forming the source region (40) and before activating the first well ions in the first implantation region (31), the manufacturing method of MIWA further comprises: implanting bulk ions of the first conductive type in a portion of the source region (40) to form a bulk region (32), and enabling the bulk region (32) to penetrate into a portion of the first implantation region (31) to short-circuit the source region (40) and the first implantation region (31). (FIG. 6).
With respect to claim 5, in view of HERMAN, implantation process parameters of the first well ions (boron) are as follows: an implantation energy is 80 keV, hence within the claimed range of 50-300 keV, and an implantation dose is 5E13 /cm2, hence within the claimed range of lEl1/cm2 - 6E14/cm2.
With respect to claim 6, an annealing time for the high-temperature annealing process of MIWA is 30 second to 1 hour, hence overlaps the claimed range of 2-200 min.
It is well settled that "[W]here 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 (CCPA 1955) (Claimed process which was performed at a temperature between 40 ºC and 80 ºC and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100 ºC and an acid concentration of 10%.); see also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.").
With respect to claim 7, the silicon carbide substrate of MIWA comprises a silicon carbide layer of the second conductive type, and both the first implantation region (31) and the second implantation region (30) are formed in the SiC layer.
With respect to claim 8, the manufacturing method of MIWA further comprises:
forming an interlayer dielectric layer (51) on the front of the silicon carbide substrate, the interlayer dielectric layer (51) burying the gate (60) inside and exposing a portion of the source region (40); and forming a source metal layer (80) on the interlayer dielectric layer (51), the source metal layer (80) being electrically connected to the source region (40).
With respect to claim 11, As best understood by the Examiner, the process of activate the first well ions (31) in the first implantation region of MIWA avoids damage to a surface of the silicon carbide substrate at the channel caused by direct multiple aluminum ion implantations.
Note that, the channel of MIWA is formed by a single implantation, therefore, the process of activate the first well ions (31) in the first implantation region of MIWA is obviously, avoids damage to a surface of the silicon carbide substrate at the channel caused by direct multiple aluminum ion implantations.
With respect to claim 12, As best understood by the Examiner, in the formed well region, the first implantation region (31) of MIWA extends laterally wider than the second implantation region (30).
With respect to claim 13, As best understood by the Examiner, an implantation energy of the aluminum ions used to form the second implantation region (30) of MIWA is higher than an implantation energy of the boron ions or boron fluoride ions, in view of HERMAN, used to form the first implantation region (80).
Firstly, the second well region (30) of MIWA being formed by deep implantation, hence higher energy, than the first well region (31), shallower, hence lower implantation energy.
Thus, the limitation is met.
Secondly, in view of HERMAN, the energy being used for the first implantation to formed well region 80 is 80 kV and the energy being used for the second implantation to formed well region 85 is 150 kV.
Thus, the limitation is met.
With respect to claim 14, As best understood by the Examiner, in view of HERMAN, the ion implantation steps for forming the first implantation region (80), the second implantation region (85), and the source region (81) are performed using a same patterned mask layer(61), so that a photoetching frequency is effectively reduced.
Response to Arguments
Applicant’s arguments with respect to new claims 11-14 have been considered but are moot. (See the rejection above).
Applicant's arguments filed June 16, 2026 have been fully considered but they are not persuasive.
MIWA, in view of HERMAN, clearly suggested, Two Different P-type Ions for Two Well regions.
Note that, first, in view of HERMAN, the channel 82 formation is explicitly based on the fast diffusion of boron ions, first well region80, as compared to the ions that formed the source region 81. Utilizing the same doping mask 61, the channel 82 is formed due to the faster diffusion coefficient of boron ions.
Secondly, the diffusion coefficient of the ion that forms the deep well 30 of MIWA does not affect the channel formation.
Thus, in view of HERMAN, the characteristics, diffusion coefficient, of boron ions being used for the first well region, base region 80, hence channel, is faster than the diffusion coefficient of aluminum ions that being used for the deep well region 30.
Moreover, the diffusion coefficient of boron ions being faster that of aluminum ions is well known in the art.
Therefore, the limitations of claim 1 are met.
MIWA, in view of HERMAN, clearly suggested, utilizing a Single Mask for all implantation.
Herman clearly suggests utilizing one implantation mask 61 for all three implantations for the first well region 80, the second, deep, well region 85 and source region 81.
Therefore, MIWA, in view of HERMAN, clearly suggest, utilizing one single implantation mask for all implantations.
MIWA, in view of HERMAN, Does Disclose a Channel formed by diffusion.
First and foremost, all ions are diffused, vertically and laterally, upon activation by high temperature annealing process.
In view of HERMAN, p-type boron ions and n-type source ions, upon activation anneal, separates from one another to form p well region 80 and source region 81.
Therefore, MIWA, in view of HERMAN, clearly shows channel diffusion by diffusion.
The limitations are met.
HERMAN clearly suggests utilizing one implantation Mask.
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant argues that HERMAN is direct to silicon MOSFET, thus cannot be combined with MIWA.
However, HERMAN, explicitly teaches utilizing one implantation mask for all implantation to form first well region 80, second deep well region 85 and source region 81.
Applicant fails to provide any evidence that technology for silicon MOSFET cannot be used for SiC MOSFET technology.
MIWA explicitly teaches SiC substrate.
Since MIWA explicitly teaches the SiC substrate, the limitation is met.
The rejection is maintained.
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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/ANH D MAI/Primary Examiner, Art Unit 2893
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