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 .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 1-5, 8, 9, 14-20, and 22-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Matsudai et al, US 20230307444 in view of Matsudai et al, US 20210091072, hereafter ‘072 in further view of Matsudai et al, US 20200303524, here after ‘524.
Regarding claim 1, Matsudai discloses : An RC IGBT, comprising: in a single chip, an active region configured to conduct both a forward load current and a reverse load current(Forward and reverse provided in a single chip [0004]) between a first load terminal at a front side(Fig. 1, #F1) of a semiconductor body of the RC IGBT and a second load terminal at a back side of the semiconductor body(#F2), wherein the active region is separated into at least an IGBT-only region(#101), an RC IGBT region(#102), a hybrid region(#103), wherein at least 90% of the IGBT-only region is configured to conduct, based on a first control signal, only the forward load current(#101 with #29 overlying #26 for forward load conduction controlled by control signal via #51 where #26 and #29 covers entire section of #101), wherein at least 90% of the RC IGBT region is configured to conduct the reverse load current(Configured for reverse load current through cathode region #31 and anode region #32 where #31 and #32 covers the entire region of #102).
Matsudai does not disclose : based on a second control signal, the forward load current, wherein at least 90% of the hybrid region is configured to conduct, based on both the first control signal and the second control signal, the forward load current.
However, in the same field of endeavor, ‘072 teaches : based on a second control signal, the forward load current(Fig. 13, different regions of RC-IGBT respond to different control signals.
It would have been obvious to one of ordinary skill in the art at the time of the invention to substitute include different control signals for different regions of an RC-IGBT because they are known equivalents and it would have yielded the predictable result. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
‘524 teaches : wherein at least 90% of the hybrid region is configured to conduct, based on both the first control signal and the second control signal, the forward load current(Fig1, two independent control signals applied in a region to connect #11 and #15 [0046-0048].
It would have been obvious to one of ordinary skill in the art at the time of the invention to control one region with two independent control signals to reduce on-resistance and switching loss (‘524 [0011]) because the known technique was recognized as part of ordinary capabilities of one skilled in the art. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Regarding claim 2, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
‘524 teaches : wherein the second control signal is different from the first control signal(independent gate voltages sent to different gate electrode #40 and #50 [0047]).
Regarding claim 3, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
Matsudai teaches : wherein the IGBT-only region, the RC IGBT region, and the hybrid region amount to at least 80% of the active region(Fig. 1, #101, #103, #102 shown to be at least 80% of an active region chip [0004]).
Regarding claim 4, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
Matsudai teaches : wherein the IGBT-only region, the RC IGBT region, and the hybrid region are spatially separated from each other(Fig.1, regions #101 and #102 separated by #103).
Regarding claim 5, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 4.
Matsudai teaches : wherein: the IGBT-only region is a first contiguous region; and/or the RC IGBT region is a second contiguous region; and/or the hybrid region is a third contiguous region(Fig. 1, #101 shares a border with #103 and #103 shares a border with #102).; and/or one or more of the IGBT-only region, the RC IGBT region, and the hybrid region exhibit a total lateral extension of at least 60% of a vertical thickness of the semiconductor body
Regarding claim 8, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
Matsudai teaches : further comprising: a drift region of a first conductivity type in the semiconductor body, wherein the drift region is shared by each of the IGBT-only region, the RC IGBT region, and the hybrid region(Fig. 2, #27 shared by all regions).
Regarding claim 9, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 8.
Matsudai teaches : further comprising: a back side emitter in electrical connection with the second load terminal and coupled to the drift region(Fig. 2, #26 connected to #14 [0052]], wherein the back side emitter is configured in accordance with the separation of the active region into at least the IGBT-only region, the RC IGBT region, and the hybrid region(#26 in #101, and #31 in #102).
Regarding claim 14, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
‘072 teaches : further comprising: a trench-mesa-pattern at the front side of the semiconductor body(#21 gate trench provided at #P1 with mesa provided between gate trench #21[0067]), wherein the trench-mesa-pattern is configured in accordance with the separation of the active region into at least the IGBT-only region, the RC IGBT region, and the hybrid region(#21, #22, and 23 provided in #101, #103, and #102, respectively).
Regarding claim 15, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 14.
‘072 teaches : wherein the trench-mesa-pattern comprises first control trenches configured to receive the first control signal and second control trenches configured to receive the second control signal, and wherein: the IGBT-only region comprises a plurality of the first control trenches(Fig. 13, #Vg1 provided to #21); the RC IGBT region comprises a plurality of the second control trenches(#Vg2 provided to #22).
‘524 teaches : and the hybrid region comprises both a plurality of the first control trenches and a plurality of the second control trenches(#GT1 and #GT2 are independent control signals [0020]).
Regarding claim 16, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 14.
‘072 teaches : wherein the trench-mesa-pattern further comprises: source trenches electrically connected to the first load terminal and arranged at least in the IGBT-only region(Fig. 2, #36 in #101 connected to #12).
Matsudai teaches : and the hybrid region(#35 connected to #12 [0111]).
Regarding claim 17, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 14.
Matsudai teaches : wherein the trench-mesa-pattern further comprises: first type mesas arranged in each of the IGBT-only region, the RC IGBT region, and the hybrid region(Fig. 11, #29 in #101, #35 in #103, and #33 in #102(, wherein each first type mesa includes a source region of the first conductivity type and a body region of the second conductivity type(#28 in #101, #34 in #103, and #32 in #102), wherein both the source region and the body region are electrically connected to the first load terminal(All connected to #12 [0048, 0103, 0083]) and wherein at least the body region isolates the source region from the drift region(#28, #34, and #32 isolates source from #27).
Regarding claim 18, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 17.
‘072 teaches : wherein the trench-mesa-pattern further comprises first control trenches configured to receive the first control signal and second control trenches configured to receive the second control signal, and wherein: the IGBT-only region comprises a plurality of the first control trenches(#21); the RC IGBT region comprises a plurality of the second control trenches(#40).
’524 teaches : and the hybrid region comprises both a plurality of the first control trenches and a plurality of the second control trenches(#GT1 and #GT2).
Regarding claim 19, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 18.
wherein: in the IGBT-only region, each first type mesa is arranged adjacent at least one of the first control trenches and each first control trench is configured to induce, in response to receiving a corresponding configuration of the first control signal, a conductive channel in the adjacent first type mesa for conduction of the forward load current(Fig. 13, #Vg1 in #101); in the RC IGBT region, each first type mesa is arranged adjacent at least one of the second control trenches and each second control trench is configured to induce, in response to receiving a corresponding configuration of the second control signal(#Vx in #103), a conductive channel in the adjacent first type mesa for conduction of the forward load current; and in the hybrid region, each first type mesa is arranged adjacent at least one of the first control trenches or adjacent at least one of the second control trenches(#Vg2 in #103).
Regarding claim 20, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 18.
‘524 teaches : wherein in the hybrid region, the first control trenches and the second control trenches are arranged in an alternating manner with respect to a first lateral direction(Fig. 1, #GT1 and #GT2 arranged in an alternating manner).
Regarding claim 22, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
wherein during a desaturation phase of the RC IGBT, the RC IGBT exhibits: a first saturation voltage between the first load terminal and the second load terminal if the first control signal is set to a value corresponding to an OFF state; and a second saturation voltage between the first load terminal and the second load terminal if the second control signal is set to a value corresponding to an OFF state, wherein the second saturation voltage is lower than the first saturation voltage(Fig. 4, #Vg2 lower than #Vg1 in an off state after #t3).
Regarding claim 23, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
Matsudai teaches : wherein the RC IGBT region exhibits a conductive-channel-width per area ratio greater than a conductive-channel-width per area ratio in the hybrid region(Fig. 1, #103 smaller in area than #102).
Regarding claim 24, Matsudai as modified by ‘072 and ‘524 discloses : A method of operating the RC IGBT of claim 1.
‘072 teaches : the method comprising: controlling the RC IGBT based on the first control signal and the second control signal(Fig. 2, #100 controlled by #Vg1 and #Vg2).
Regarding claim 25, Matsudai as modified by ‘072 and ‘524 discloses : The method of claim 24, wherein during a desaturation phase of a forward conduction state of the RC IGBT, an OFF-potential of the second control signal is different from an OFF-potential of the first control signal(Fig. 4, off state of #Vg1 different from #Vg2).
Claim(s) 6, 7, and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Matsudai et al, US 20230307444 in view of Matsudai et al, US 20210091072, hereafter ‘072 in further view of Matsudai et al, US 20200303524, here after ‘524 in further view of Baburske, US 20220093585
Regarding claim 6, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 1.
Matsudai as modified by ‘072 and ‘524 does not disclose : further comprising: a diode-only region, at least 90% of which is configured to conduct only the reverse load current.
However, in the same field of endeavor, Baburske teaches : further comprising: a diode-only region, at least 90% of which is configured to conduct only the reverse load current(#1-22 configured for reverse load current [0059]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to apply the teachings of Baburske to Matsudai, ‘072, and ‘524 to include a diode region in a RC-IGBT for conduction and switching purposes (Baburske [0039]).
Regarding claim 7, Matsudai as modified by ‘072, ‘524, and Baburske discloses : The RC IGBT of claim 6.
Baburske teaches : wherein no control trench and/or no source region is present in the diode-only region(#1-22 has no source [0060] and is independent of IGBT region [0062]).
Regarding claim 21, Matsudai as modified by ‘072, ‘524 discloses : The RC IGBT of claim 14.
Matsudai as modified by ‘072, ‘524 does not disclose : further comprising: a barrier region of the first conductivity type that couples the trench-mesa-pattern in the IGBT-only region and in the hybrid region to a drift region of a first conductivity type in the semiconductor body, wherein the drift region is shared by each of the IGBT-only region, the RC IGBT region, and the hybrid region, wherein a dopant concentration of the barrier region is greater than a dopant concentration of the drift region.
However, in the same field of endeavor, Baburske teaches : further comprising: a barrier region of the first conductivity type that couples the trench-mesa-pattern in the IGBT-only region and in the hybrid region to a drift region of a first conductivity type in the semiconductor body(Fig. 7, #105 through three regions of device), wherein the drift region is shared by each of the IGBT-only region, the RC IGBT region, and the hybrid region(#105 single layer laterally structured through all regions [0125]), wherein a dopant concentration of the barrier region is greater than a dopant concentration of the drift region(#105 dopant concentration may be at least 100 times that of #100 [0124]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to apply the teachings of Baburske to Matsudai, ‘072, and ‘524 to include a barrier layer in contact with the drift region to reduce load current (Baburske [0155]).
Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Matsudai et al, US 20230307444 in view of Matsudai et al, US 20210091072, hereafter ‘072 in further view of Matsudai et al, US 20200303524, here after ‘524 in further view of Pfirsch et al, US 20160035867.
Regarding claim 10, Matsudai as modified by ‘072 and ‘524 discloses : The RC IGBT of claim 9.
Matsudai teaches : wherein the back side emitter comprises: a first section of a second conductivity type in a portion of the active region where the IGBT-only region is present(#26 in #101).
Matsudai as modified by ‘072 and ‘524 does not disclose : a second section including both first subsections of a first conductivity type and second subsections of the second conductivity type in a portion of the active region where the RC IGBT region is present; and a third section in a portion of the active region where the hybrid region is present and having a conductivity type configured in accordance with at least one of the first section and the second section.
However, in the same field of endeavor, Pfirsch teaches : a second section including both first subsections of a first conductivity type and second subsections of the second conductivity type in a portion of the active region where the RC IGBT region is present; and a third section in a portion of the active region where the hybrid region is present and having a conductivity type configured in accordance with at least one of the first section and the second section(Fig. 2, Different combinations of #5 and #6 in #151 and #9a and #9b in #152 where doping concentrations may vary continuously or step-wise[0066]).
It would have been obvious to one of ordinary skill in the art at the time of the invention to substitute the varied doping concentrations/conductivity types to improve RC-IGBT with less adverse impact on other device characteristics (Pfirsch [0005]) because they are known equivalents and it would have yielded the predictable result. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claim(s) 11-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Matsudai et al, US 20230307444 in view of Matsudai et al, US 20210091072, hereafter ‘072 in further view of Matsudai et al, US 20200303524, here after ‘524 in further view of Pfirsch et al, US 20160035867 in further view of Baburske, US 20220093585.
Regarding claim 11 Matsudai as modified by ‘072, ‘524, and Pfirsch discloses : The RC IGBT of claim 10.
Matsudai as modified by ‘072, ‘524, and Pfirsch does not disclose : wherein the first section of the back side emitter: exhibits, with respect to a total lateral extension of the first section along a first lateral direction and at a certain vertical level, an average dopant concentration of at least 2*1015 cm-3, and/or is displaced from the RC IGBT region by at least the hybrid region; and/or exhibits, at a certain vertical level and along at least one of the first lateral direction and a second lateral direction, a variation of the dopant concentration.
However, in the same field of endeavor, Baburske teaches : wherein the first section of the back side emitter: exhibits, with respect to a total lateral extension of the first section along a first lateral direction and at a certain vertical level, an average dopant concentration of at least 2*1015 cm-3(#103 may range from
10
16
c
m
-
3
to
10
18
c
m
-
3
[0108]) and/or is displaced from the RC IGBT region by at least the hybrid region; and/or exhibits, at a certain vertical level and along at least one of the first lateral direction and a second lateral.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have a certain doping concentration with routine experiment and optimization. In re Woodruff, 16 USPQ2d 1935, 1937 (Fed. Cir. 1990).
Regarding claim 12, Matsudai as modified by ‘072, ‘524, and Pfirsch discloses : The RC IGBT of claim 10.
Matsudai as modified by ‘072, ‘524, and Pfirsch does not disclose : wherein each of the first subsections of the second section of the back side emitter exhibits, with respect to a respective total lateral extension of each first subsection along the first lateral direction and at a certain vertical level, an average dopant concentration of at least 1*1018 cm-3.
However, in the same field of endeavor, Baburske teaches : wherein each of the first subsections of the second section of the back side emitter exhibits, with respect to a respective total lateral extension of each first subsection along the first lateral direction and at a certain vertical level, an average dopant concentration of at least 1*1018 cm-3(Various embodiments with different doping concentrations may be applied [0103-0109]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have a certain doping concentration with routine experiment and optimization. In re Woodruff, 16 USPQ2d 1935, 1937 (Fed. Cir. 1990).
Regarding claim 13, Matsudai as modified by ‘072, ‘524 and Pfirsch discloses : The RC IGBT of claim 10.
Matsudai as modified by ‘072, ‘524 and Pfirsch does not disclose : further comprising: a field stop region the first conductivity type arranged in contact with both the drift region and with each of the first section, the second section, and the third section of the back side emitter, wherein a dopant concentration of the field stop region is greater than a dopant concentration of the drift region.
However, in the same field of endeavor, Baburske teaches : further comprising: a field stop region the first conductivity type arranged in contact with both the drift region and with each of the first section(Fig. 3, #108), the second section, and the third section of the back side emitter(Fig. 3 and Fig. 4, #108 in #1-22 and #1-21), wherein a dopant concentration of the field stop region is greater than a dopant concentration of the drift region(#108 has a higher dopant does compared to #100 [0098]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to apply the teachings of Baburske to Matsudai, ‘072, ‘524 and Pfirsch to include a field stop layer to decrease a thickness of a drift region (Baburske [0129]).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: US 20240379830 – Dual gate power semiconductor .
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/D.T./Examiner, Art Unit 2897 /CHAD M DICKE/Supervisory Patent Examiner, Art Unit 2897
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