Interview (Leti): How a new platform helps designers get the most out of FD-SOI for IoT, ULP

CEA-Leti Clean Room (© Pierre Jayet)
CEA-Leti Clean Room (© Pierre Jayet)

A driving force in FD-SOI, Leti recently announced a service called Silicon Impulse®, a new FD-SOI platform for IoT & ultra-low-power (ULP) apps that helps start-ups, SMEs and large companies evaluate, design, prototype & move to volume. Olivier Thomas, who’s in charge of the program and Ali Erdengiz, who’s Business Development Manager for Leti explain how it works.

 

Advanced Substrate News (ASN): What exactly is Silicon Impulse? What services does it offer?

OThomas2
Olivier THOMAS is the project leader of Silicon Impulse for Leti.

Olivier Thomas (OT): Silicon Impulse provides design services from emulation to test program development and qualification (emulation, advanced building blocks and IPs access, full control design flow, industrial MPW, packaging and board, test and qualification).

So you can consider Silicon Impulse as a silicon enablement and development platform: a unique IC prototype development and production hand-off partner for companies in need of the latest low-power semiconductor technologies and heterogeneous integration solutions (FD-SOI, BEOL NVM, MEMS, 3D…). We work with a strong network of industrial partners and offer a single entry point along product maturation.

Silicon Impulse leverages Leti’s* and List’s** expertise as well as top industrial partners belonging to a global network of experts in analog, RF, digital and memory design, as well as hardware/software-integrated solutions.

CEA-Leti Clean Room (©Pierre Jayet)

 

In a nutshell, Silicon Impulse offers:

  • a pool of expertise from device to system
  • access to world-class, leading-edge technologies
  • regularly scheduled industrial multi-project wafer (MPW) shuttles
  • access to a proven supply chain
  • customized collaboration to fit partner needs

[Editor’s note: Click here to download the Silicon Impulse brochure.]

ASN: Who is it aimed at?

Ali Erdengiz is Business Development Manager for Leti/List.
Ali Erdengiz is Business Development Manager for Leti/List.

Ali Erdengiz (AE): We saw that the increasing cost of leading semiconductor technologies, the level of expertise, tools and resources required to develop innovative products using such advanced processes can make it really challenging for new entrants (product and solution innovators). So CEA Leti created the Silicon Impulse initiative to help innovative companies to get their projects off the ground. We provide an advanced silicon development platform, help them develop their IC and/or subsystem and then hand it off to the production supply chain.

We did this because we see that today’s new markets are driven by a variety of applications and new players – it’s not just the big players scaling for PCs and mobiles anymore. IoT is a great opportunity for the emergence of innovations and ideas from new entrants. We’ve been getting more and more requests from partners looking to integrate the advanced technologies developed in Leti such as BEOL NVM and MEMS. They’re thinking outside of the box, so they are also interested in using 28nm FD-SOI while requesting advanced features and specific performance at low-voltage. Leti has always done technology research. Now with Silicon Impulse we provide a new service in collaboration with other industrial partners to help companies evaluate, design, prototype, and launch their products.

ASN: If FD-SOI design is so easy and so close to what designers have done in bulk, why do they need this sort of service?

Leti and List have a long history of launching innovation, as seen here in the CEA-Leti Showroom (©Pierre Jayet)

 

OT: Indeed, one can easily migrate from bulk to FD-SOI and benefit immediately from its low power/low leakage characteristics. However, we’ve seen that many of the companies that port their circuits to FD-SOI don’t exploit the full potential of the technology. Silicon Impulse leverages Leti’s strong expertise and experience in FD-SOI technology from device to Digital/RF modeling and advanced design solutions and maximizes the gains of the technology. Our competence center provides its industrial partners with quick access to information, know-how and silicon proven advanced design and architecture solutions to efficiently manage performance, power consumption and process variability. Here are some examples: PVT sensors, timing fault tracking, control theory module (i.e. algorithm to figure out the optimum energy point), fast feedback loop on the top of tailored charge pump and other blocks to back bias efficiently.

In addition, Leti’s Silicon Impulse’s expertise is not limited to designing FD-SOI IC’s. Leti brings a wealth of system knowledge and application know-how from device technology through embedded software that ensures full success and differentiation for its partners’ projects.

ASN: Why should designers consider FD-SOI?

OT: The 28nm/22nm technology nodes are seen as a long-lived technology node and a sweet spot for performance, power and cost. FD-SOI is optimized for low-voltage, low-power applications that can nevertheless need high performance.

For digital design, the extended range (+/-2V) of back biasing along with PVT sensors, timing fault tracking, theory control module and fast feedback loops controlling the back bias enable efficient process compensation and energy optimization for a wide range of applications (E. Beigne et al. ISSCC’14).

For SRAM design, the un-doped planar technology offers a large portfolio of SRAM bit-cells (High-density, Low power, High-performance) enabling very good performance over a wide voltage range. The Single P-Well bit-cell architecture combined with a wide back bias range enables both low operating voltage and fast access time. In sleep mode, the back bias can be set to minimize the bit-cell standby leakage current and the data retention voltage (O. Thomas et al. IEDM’14).

For RF design, one key aspect shown in the paper presented at ISSCC 15 is the continuous re-configurability through VT adjustment by the back-gate. The Power Amplifier discussed in the paper can pass from a high-linearity/high-efficiency state to a high power state by continuous linear tuning; something that cannot be done in other technologies. At the same time, the 28 FD-SOI allows designers reach much higher FT/Fmax than bulk. The result is higher available gain in mm Wave (as shown in our example at 60GHz). This approach drastically reduces the PA’s power consumption in 90% of the use cases, thus enabling WiGig for example in mobile applications.

ASN: What are the logistics for getting started?

OT, AE: Silicon Impulse can help innovators with their projects from concept through production hand-off. To get started on a project, we do a business review to determine where and how Silicon Impulse can contribute. We can provide architectural advice and shape the product from a very high level, develop a feasibility study and make recommendations as to how to implement the system. Leti and its partners can provide unique IP and/or technology components such as foundation IP or more complex system level IP blocks, RF, MEMS, 3D components and any other advanced technology to shape a truly unique and advanced yet manufacturable product. Another layer of contribution of Leti, List would be in providing embedded software to complete the whole product. So Silicon Impulse’s involvement can be limited to architectural consulting or extended to developing and delivering the whole system or anything in between.

Construction of an extension to the Minatec campus is now underway, which will be the new home to Leti’s Silicon Impulse® service. (Architect’s rendering of the IC Design Competence Center building, north view shown here, ©Futur A Architectes)

 

ASN: You’re running multi-project wafer (MPW) shuttles – can you tell us more about that?

OT: Leti offers its MPW shuttles to open the doors to a wider set of users and projects (some of whom might not have access to or be ready yet for full service foundries). An MPW shuttle serves two main purposes:

  • Enable innovators to test their ideas, especially mixed-signal, analog or RF or any new IP that would require silicon validation in FD-SOI
  • Provide an affordable platform for startups and other small companies to build their prototypes and run small volumes until they can raise enough funds and/or demonstrate market traction to build their own mask set.

However, we’ll also be making an announcement in the near future with details of schedules for planned MPW shuttles with our industrial partners.

ASN: How long will it take to get to a working design?

AE: This is project dependent, but leveraging Leti’s experience and already proven IPs and methodologies it is likely that our partners will develop a successful design even faster than if they did it on their own regardless of whether they used FD-SOI or bulk. Using FD-SOI for digital design targeting low power without compromising performance will certainly get you there faster than using bulk. In addition, the intrinsic characteristics of FD-SOI and much better control of device variability will accelerate analog and RF design and reduce time to market.

ASN: Will the design then be transferable to a full-service, high-volume fab?

OT: The purpose of Silicon Impulse is to ease IC prototype development and enable/accelerate production ramp-up. Silicon Impulse completes the Leti R&D offering by transferring the technology into a manufacturable product. The production is then handed off to a full service fab and/or supply chain partner. We’ll begin announcing the names of these partners shortly.

For information on contacting Leti’s Silicon Impulse service, click here.

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Olivier THOMAS is the project leader of Silicon Impulse for Leti. He received the M.S. Electrical Engineering degree from ISEN in 2001 and the Ph.D. degree from the Telecom ParisTech in 2004. He joined the CEA-LETI Laboratory in the Center for Innovation in Micro & Nanaotechnology (MINATEC), Grenoble, France in 2005. From 2005 to 2014 his research work was focused on advanced low-power digital and memory design in leading edge SOI technologies (PDSOI, FDSOI) and heterogeneous technology co-integration (ReRAM, 3DVLSI). From 2010 to 2012, he was a visiting researcher at Berkeley Wireless Research Center (BWRC) of University of California at Berkeley. He worked on methodologies to characterize on large-scale static/dynamic SRAM performances. From 2012 to 2014, he launched and led the Leti’s advanced memory design activity. He is author or co-author of 75 articles in international refereed journals and conferences and 25 patents.

Ali Erdengiz is Business Development Manager for Leti/List. He has spent 20 years in Silicon Valley and held various engineering, marketing, product and business unit management functions at companies such as ST Micro, National Semiconductor, Fujitsu, Altera, Abound Logic and eSilicon. Ali holds a BSEE from ESME, an MSEE from Université Parix XI and an MBA from San Jose State University.

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Minatec_aerial_lores
Leti is located in the heart of the Minatec innovation campus in Grenoble. Minatec was founded by CEA Grenoble, INPG (Grenoble Institute of Technology) and local government agencies. The project combines a physical research campus with a network of companies, researchers and engineering schools. As such, Minatec is home to 2,400 researchers, 1,200 students, and 600 business and technology transfer experts on a 20-hectare (about 50-acre) state-of-the-art campus with 10,000 m² of clean room space. An international hub for micro and nanotechnology research, the campus is unlike any other R&D facility in Europe. (Photo: courtesy Minatec)

*CEA-Leti is a research-and-technology organization with a large and word class expertise from device through system integration. It specializes in nanotechnologies and their applications. NEMS and MEMS are also at the core of its activities. Leti is capable of not only developing semiconductor devices (analog, mixed-signal, RF, digital, MEMS) but also integrating them into subsystems using PCB, MCM, 2.5D and 3D technologies as well as developing embedded and application software to deliver full system level solutions.

 

**A sister organization to CEA-Leti, CEA-List conducts R&D in fields that create value for the economy and society. As such, the primary mission is to give businesses the tools they need to turn their innovative ideas into marketable products.

 

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