“While the determination established that Wolfspeed’s petition did not contain substantially the same prior art, Vidal emphasized that: advanced bionics The PTAB should consider whether substantially the same legal claims have been brought forward as previously brought. “
On March 30, US Patent and Trademark Office (USPTO) Director Kathi Vidal made the following decision: spontaneously Examination of directors overturning a Patent Trial Board (PTAB) decision. between the parties Review (IPR) proceedings filed by semiconductor company Wolfspeed.In the latest in her series spontaneously Director Vidal argued that Wolfspeed’s asserted prior art was essentially the same as other prior art asserted against the same Purdue patent claims in previous IPR proceedings rejected by the PTAB. It was ruled that the decision was erroneous.
Wolfspeed IPR Petition Claims Prior Art on MOSFET, Transistor Topologies
The patent at issue in Wolfspeed’s IPR petition is US Patent No. 7,498,633. High voltage power semiconductor device, owned by Purdue University. The ‘633 patent claims a metal oxide semiconductor field effect transistor (MOSFET) fabricated with a current spreading semiconductor layer formed in front of a drift semiconductor layer. The use of current spreading layers claimed by the ‘633 patent addresses a problem in MOSFET manufacturing where a reduction in specific on-state resistance typically results in a reduction in the blocking voltage of the semiconductor device. Purdue previously asserted the ‘633 patent claim against Wolfspeed in his October 2021 lawsuit filed in the Central District of North Carolina.
Wolfspeed’s IPR petition challenged obviousness based on the combined prior art of claims 9 through 11 of the Purdue ‘633 patent. Both of Wolfspeed’s obviousness claims relied on U.S. Patent Application No. 20040119076 (“Ryu”), which teaches MOSFETs. Wolfspeed’s IPR petition filed U.S. Pat. (“Depetro”). or U.S. Patent No. 5,171,705 (“Choy”). In particular, both Depetro and Choy, along with Ryu’s MOSFET, support Wolfspeed’s argument for obviousness by teaching multiple spaced-apart p-type base-contact regions, and the robustness of semiconductor devices. We have achieved a reduction in on-resistance without sacrificing performance.
PTAB had to consider material differences that reduce device durability
The PTAB denied commencement of Wolfspeed’s IPR petition under its discretionary denial powers codified at 35 USC § 325(d).Applying the framework Advanced Bionics v. MED-EL Electrical Medical Devices, an earlier PTAB decision from 2020, the PTAB determined that both Deptro and Choy are substantially the same prior art as U.S. Patent No. 6,413,822 (“Williams”). Williams is another defendant in a patent infringement lawsuit filed by Purdue University in U.S. District Court. In his IPR petition for STMicroelectronics, Williams similarly relied on teaching his topology of specific transistors designed to reduce on-resistance, as claimed in Purdue’s ‘633 patent. rice field.of he applies the second step advanced bionics In response to Wolfspeed’s IPR petition, the PTAB found that Wolfspeed’s failure to address whether there was an error in rejecting an earlier petition filed by STMicroelectronics led to Wolfspeed’s rejection of the agency. bottom.
in her spontaneously Vidal held that the PTAB was erroneous in its refusal to enforce Wolfspeed’s petition because Williams was not substantially the same prior art as Depetro and Choy. In particular, she argues that she did not adequately consider the material differences between Williams and his Wolfspeed purported prior art, particularly the fact that his Williams’ transistor topology results in less robust semiconductor devices. accused the PTAB. That particular disclosure was the primary reason the PTAB refused to implement her STMicroelectronics IPR petition for weakening Williams and Ryu’s reasons for joining his MOSFETs.
Conversely, neither Deptro nor Choy contained any disclosure of the lack of robustness resulting from the use of the transistor topologies claimed in either prior art document. “Indeed, petitioner relies on DePetro’s teachings and the testimony of its experts to argue that DePetro’s transistor-his topology, unlike Williams’ transistor-his topology, does not compromise robustness. ,” Vidal wrote.
Vidal reviews welcome, but ‘compelling merit’ reviews remain confusing
Vidal reversed the PTAB’s refusal to sue, but Wolfspeed’s petition was remanded for the PTAB to properly consider its § 325(d) investigation. advanced bionicsAlthough the Director’s review decision established that Wolfspeed’s petition did not contain substantially the same prior art, Vidal emphasized that: advanced bionics We request the PTAB to consider whether it presented substantially the same legal arguments previously raised in STMicroelectronics’ IPR petition.
The recent ruling is just the latest in a string of rulings. spontaneously A review of PTAB decisions issued by the highest authority within the USPTO.Vidal was granted last August spontaneously Review to confirm the PTAB’s ruling that interference estoppel does not prevent parties from pursuing IPR proceedings to challenge patents in the same issue. Then, in his late February of this year, Vidal made the following decision. spontaneously Directors’ review to clarify impact of previous “Compelling Merit” memo on discretionary denial framework apple vs fintibAnd just one day before the event wolf speed In Director’s Review, she vacated another decision to reject the agency in a petition filed by Google.
Vidals spontaneously But industry insiders who reviewed her persuasive merits judgment in February argue that the decision will do little to clear up confusion under U.S. law. dummy analysis.
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Author: Don Scarpo
