By Ronald M. Martino, Vice President, i.MX Applications Processor and Advanced Technology Adoption, NXP Semiconductors
At NXP, we’re very excited about the prospects for our new i.MX 7 and 8 series of applications processors, which we’re manufacturing on 28nm FD-SOI.
As noted in part 1 of this article series, the new i.MX 7 series, which leverages the 32-bit ARM v7-A core, is targeting the general embedded, e-reader, medical, wearable and IoT markets, where power efficiency is paramount. The i.MX 8 series leverages the 64-bit ARM v8-A series, targeting automotive applications, especially driver information systems, and well as high-performance general embedded and advanced graphics applications.
Choosing an FD-SOI solution gave our designers some specific tools that helped them to more easily and robustly deliver the features our customers are looking for. Here in part 2, we’ll look a little more deeply into the markets each of these chip families is targeting, and the role FD-SOI plays in helping us meet our specs.
Announced last June, the first members of our new 7 series — the i.MX 7Solo and i.MX 7Dual product families — will be hitting the market shortly. We’ve been shipping samples since last year, and the response has been tremendous. (You can read about the i.MX 7 IoT ecosystem we’re helping create for our customers here and support for wearable markets here.)
Our i.MX 7 customers are building products for power- and cost-sensitive markets. That of course includes a vast array of innovative IoT solutions and wearables, but also solutions for other parts of the embedded market like handheld point-of-sale (POS) and medical devices, smart home controls and industrial products. The i.MX 7 series also continues NXP’s industry leading support for the e-reader market via integration of an advanced, fourth-generation EPD controller.
For all these markets, excellent performance is very important, but both dynamic and static power figures are really key. When you’re creating a system with power efficient processing and low-power deep sleep modes, you enable a new tier of performance-on-demand, battery-operated devices that are lighter and cheaper, and in a virtuous cycle require smaller batteries.
The next members of the NXP i.MX 7 series combine ultra-low power (dynamically leveraging the reverse back biasing you can do with FD-SOI) and performance-on-demand architecture (boosted when needed with FD-SOI’s forward back-biasing). It’s the industry’s first general purpose microprocessor family to incorporate both the ARM® Cortex®-A7 and the ARM Cortex-M4 cores (customers can choose between single or dual A7 cores). These technologies, together with our new companion PF3000 power management IC, unleash the potential for dramatically innovative, secure and power efficient end-products for wearable computing and IoT applications.
The initial offering of i.MX 7 was designed (on 28nm bulk) with Cortex-A7 cores operating up to 1 GHz, while the Cortex-M4 core operates at up to 200 MHz. The Cortex-A7 and Cortex-M4 achieve processor core efficiency levels of 100 microWatts (μW) /MHz and 70 μW /MHz respectively.
A Low Power State Retention (LPSR), battery-saving mode can be improved by FD-SOI and consumes only 250 μW, representing a 3x improvement over our previous generation (on 40nm bulk). That’s almost 50% better than our competitors. Plus it minimizes wake up times without requiring Linux reboot, while supporting DDR self-refresh mode, GPIO wakeup, and memory state retention.
The next members of the i.MX 7 series, with FD-SOI dynamic back-biasing, enable different blocks to be reverse or forward back-biased on the fly to attain always-optimal power savings or performance. Additional power optimization features are enabled to achieve leadership power efficiency. We’ve optimized FD-SOI dynamic back-biasing to enable performance-on-demand architecture through which the i.MX 7 series meets the bursty, high-performance needs (this is when forward back-biasing kicks in) of running Linux, graphical user interfaces, high-security technologies like Elliptic Curve Cryptography, as well as wireless stacks or other high-bandwidth data transfers with one or multiple Cortex-A7 cores.
When high levels of processing are not needed, low-power modes kick in with reverse back biasing of the critical subsystems, and the ongoing, real-time work is carried on by the smaller, lower powered Cortex-M4.
All things considered, it’s perhaps no surprise that we expect i.MX 7 series solutions for cost-sensitive markets to be a key driver of our long-term i.MX portfolio expansion.
Our new i.MX 8 series portfolio, based on 28nm FD-SOI process technology, targets highly-advanced driver information systems and other multi-media intensive embedded applications. It incorporates those same key attributes as the i.MX 7, but extends them into realms the industry has never experienced. We believe the i.MX 8 series is poised to revolutionize interactivity in multimedia and display applications across all kinds of industries.
i.MX 8 incorporates innovations in the processor — complex graphics, vision, virtualization and safety to help revolutionize interactivity for a wide range of uses in many, many markets. The capabilities of this family is broad, but one of the places it’s going to be the biggest game-changer is in what is becoming the e-cockpit of your car.
For almost two decades, SOI has shone in the embedded processing world. In addition, NXP counts every major automotive maker in the world amongst its customers for our devices. Entering the new e-cockpit frontier, 28nm FD-SOI is the logical choice in making the i.MX 8 series meet and exceed the stringent requirements of top automotive OEMs for years to come.
The i.MX 8 series leverages ARM’s V8-A 64-bit architecture in a 10+ core complex that includes blocks of Cortex-A72s and Cortex-A53s. All the FD-SOI advantages discussed above for the i.MX 7 are also being brought to bear here (the power envelope for automotive designers being extremely strict). But in the hot and electrically noisy automotive environment, FD-SOI also plays an important role in ensuring robust operation.
The way we see it, your car’s multimedia centric e-cockpit will revolve around the i.MX 8, a single chip that drives all displays from infotainment to heads-up-displays (HUD) to instrument clusters. It’s optimized for the intelligent transfer of data and information management from multiple subsystems within the IC – as opposed to only delivering raw performance through one or two processing blocks.
For drivers and passengers alike, we’re looking at a very different world: one that includes the spread of advanced heads-up displays, intuitive gesture control, natural speech recognition, augmented reality, enhanced convenience and device connectivity. (I wrote a blog exploring the possibilities last fall – you can read it here.)
And of course, it will be secure from hackers, and fail-safe for critical systems.
From our customers’ standpoint, they can design a single hardware platform and scale it across multiple market segments with the unique approach to pin and software compatibility within the i.MX product families.
The i.MX family has been leveraged in over 35 million vehicles since it was first launched in vehicles in 2010. So with all these new features, and low-power and robust performance, we see a very bright future for FD-SOI and the i.MX 8 in automotive. It’s going to be a great ride.
By Ronald M. Martino, Vice President, i.MX Applications Processor and Advanced Technology Adoption, NXP Semiconductors
The latest generations of power efficient and full-featured applications processors in NXP’s very successful and broadly deployed i.MX platform are being manufactured on 28nm FD-SOI. The new i.MX 7 series leverages the 32-bit ARM v7-A core, targeting the general embedded, e-reader, medical, wearable and IoT markets, where power efficiency is paramount. The i.MX 8 series leverages the 64-bit ARM v8-A series, targeting automotive applications, especially driver information systems, as well as high-performance general embedded and advanced graphics applications.
Over 200 million i.MX SOCs have been shipped over six product generations since the i.MX line was first launched (by Freescale) in 2001. They’re in over 35 million vehicles today, are leaders in e-readers and pervasive in the general embedded space. But the landscape for the markets targeted by the i.MX 7 and i.MX 8 product lines are changing radically. While performance needs to be high, the real name of the game is power efficiency.
The bottom line in chip manufacturing is always cost. A move from 28nm HKMG to 14nm FinFET would entail up to a 50% cost increase. Would it be worth it? While FinFETs do boast impressive power-performance figures, for applications processors targeting IoT, embedded and automotive, we need to look beyond those figures, taking into account:
In fact, both NXP and the former Freescale have extremely deep SOI expertise. Freescale developed over 20 processors based on partially-depleted SOI over the last decade; and NXP, having pioneered SOI technology for high-voltage applications, has dozens of SOI-based product lines. So we all understand how SOI can help us strategically leverage power and performance. For us, FD-SOI is just the latest SOI technology, this time with a design flow almost identical to bulk, but on ultra-thin SOI wafers and some important additional perks like back-biasing.
When all the factors we care about for the new i.MX processor families are tallied up, FD-SOI comes out a clear winner for i.MX SOCs.
For our designers, here’s why FD-SOI is the right solution to the engineering challenges they faced in meeting evolving market needs.
In terms of power, you can lower the supply voltage (Vdd) – so you’re pulling less power from your energy source – and still get excellent performance. Add to that the dynamic back-biasing techniques (forward back-bias improves performance, while reverse back-bias reduces leakage) available with FD-SOI (but not with FinFETs), you get a very large dynamic operating range.
By dramatically reducing leakage, reverse back-biasing (RBB) gives you good power-performance at very low voltages and a wide range of temperatures. This is particularly important for IoT products, which will spend most of their time in very low-power standby mode followed by short bursts of performance-intense activity. We can meet the requirements for those high-performance instances with forward back-biasing (FBB) techniques. And because we can apply back-biasing dynamically, we can specify it to meet changing workload requirements on the fly. [Editor’s note: click here and here for helpful ASN articles with descriptions and discussions of back-biasing, which is also sometimes called body-biasing.]
Devices for IoT also have major analog and RF elements, which do not scale nearly so well as the digital parts of the chip. Furthermore analog and RF elements are very sensitive to voltage variations. It is important that the RF and analog blocks of the chip are not affected by the digital parts of a chip, which undergo strong, sudden signal switching. The major concerns for our analog/RF designers include gain, matching, variability, noise, power dissipation, and resistance. Traditionally they’ve used specialized techniques, but FD-SOI makes their job much easier and results in superior analog performance.
In terms of RF, FD-SOI greatly simplifies the integration of RF blocks for WiFi, Bluetooth or Zigbee, for example, into an SOC.
Soft error rates (SER)* are another important consideration, especially as the size and density of SOC memory arrays keep increasing. Bulk technology gets worse SER results with each technology node, while FD-SOI provides ever better SER reliability with each geometry shrink. In fact, 28nm FD-SOI provides 10 to 100 times better immunity to soft-errors than its bulk counterpart.
Our process development strategy has always been to leverage foundry standard technology and adapt it for our targeted applications, with a focus on differentiating technologies for performance and features. We typically reuse about 80% of our technology platform, and own our intellectual property (IP). Looking at the ease of porting existing platform technology and IP, and analyzing die size vs. die cost, again, FD-SOI came out the clear choice.
In terms of manufacturing, FD-SOI is a lower-risk solution. Integration is simpler, and turnaround time (TAT) is much faster. 28nm FD-SOI is a planar technology, so it’s lower complexity and extends our 28nm installed expertise base. Throughout the design cycle, we’ve worked closely with our foundry partner, Samsung. They provided outstanding support, and very quickly reached excellent yield levels, which is of course paramount for the rapid ramp we anticipate on these products.
In the second part of this article, we’ll take a look at the new i.MX product lines, and why FD-SOI is helping us make those game-changing plays for specific markets.
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* Soft errors occur when alpha or neutron particles hit memory cells and change their state, giving an incorrect read. These particles can either come from cosmic rays, or when radioactive atoms are released into the chips as materials decay.
By Duncan Bremner, CTO SureCore Limited
Editor’s note: sureCore just announced availability of its 28nm FD-SOI memory compiler (press release here), which supports the company’s low-power, Single and Dual Port SRAM IP. Here, the company’s CTO explains why this IP is getting such impressive results.
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Recently, sureCore announced results from a 28nm FD-SOI test chip that showed dynamic power savings exceeding 75% and static power cuts up to 35% (when compared against a number of current commercial offerings), while only incurring a 5-10% area penalty for its ultra-low power SRAM IP.
And while this data is easily substantiated as shown in Figure 1, the sceptical industry pundits have raised questions that fall into two camps: (a) That can’t be done; or (b) How did they manage that? In answer to both of these questions, here’s a quick look at the history and engineering strategy that we adopted to deliver these results.
Looking back to the early days of sureCore, SRAM fascinated us because despite many process iterations, the SRAM in use today bears a striking resemblance to the SRAM architectures that existed in the ’70s and ’80s. We concluded that no one had really taken a “blank-sheet-of-paper” look at the architecture for over 40 years. Recognising the growing importance of power efficiency for SoCs targeting forward-looking applications such as wearables, IoT, and other mobile devices, we examined power consumption in detail, and began by investigating how we could reduce SRAM power to a level attractive to the next generation of power critical, SoC designers.
Our starting point differed significantly from the traditional approach to SRAM R&D that typically starts at the bit cell. We recognised that the basic bit cell is fixed by the foundry; it’s a piece of electronics that is carefully optimised for fabrication. Modern bit cells are designed by the foundries who tend to put an emphasis on the broadest possible manufacturability drivers; yield and faster-time-to-volume as opposed to more performance-centric metrics. Their focus is on the front-end process optimisation, area and yield.
The basic rule of R&D fabless foundry engagement has been, “use the storage array – you won’t get a better packing density.” Consequently, the application use model had become separated from the technology — ‘faster or cheaper’ became the industry’s mantra instead of ‘faster and better’. This resulted in SRAM design teams focusing on how to build more sensitive read amplifiers to detect the signals, and better write amplifiers to drive the signal on to the bit cell. Not much time was spent looking at the fundamental architecture and asking: “Is this the best way?”
sureCore decided to take a more holistic view and stood back from the whole problem. We started with a clean sheet of paper and asked, “Where does the power go when you start storing data on SRAM?”
We discovered that a lot of the power is consumed hauling parasitic capacitance around. Our design strategy was therefore very simple; we developed a system architecture to optimize power while still retaining the area advantages of the standard foundry bit cell.
Simply stated, we architected the internal block architecture of SRAM by splitting the read amplifier function into a local and global read amplifier, thus dividing the capacitive load from the word-line, only driving the areas being addressed and not the whole array. This resulted in significant dynamic power savings during the read cycle. In a similar fashion, we reduced the write cycle power by a similar amount. Whilst hierarchical solutions are not new, the sureCore “secret sauce” is at circuit level developed by our engineering teams leading to not only significant power savings, but also comparable performance levels.
Our “blank sheet” approach delved deep; right down to the fundamental device physics level. Our strategic partners, Gold Standard Simulations — recognised world leaders in modelling devices at the atomic level and experts in nano-scale process nodes, helped us to understand the behaviour and limitations of processes at nodes below 28nm at a device level and bit cell level. Combining this fundamental device understanding with excellent circuit design and system analysis skills, we’ve identified where existing SRAM solutions waste power, and architected our solution to avoid this; we deliver power savings without the added complexity of write and read-assist.
At the outset, we determined it was important that our IP be process-independent. sureCore IP is based on architecture and circuit techniques rather than a reliance on process features. The result of this is technology that can reduce power in standard bulk CMOS, but is equally applicable to newer FinFET or FD-SOI processes and across all geometries, even down to 16nm and below. We believe our approach is paying off and, because we insisted in retaining the foundry optimised bit cell, sureCore’s technology can be retrofitted into existing designs enabling extended product life cycles.
This is our basic technology story… a start-up deciding to take a fresh look at an old technology and dramatically improving power performance over 75% compared with existing solutions. This is a new approach to SRAM power consumption for power sensitive applications and it delivers tangible battery life benefits to both the end user and the FD-SOI designers. Today’s FD-SOI technology is optimised for low power applications, bringing extended battery life to the nascent markets of wearables and IoT.
Just a month into 2016 and we already have a raft of FD-SOI news from Samsung, GlobalFoundries, NXP/Freescale, Renesas and more. And of course RF-SOI continues ever stronger.
Here’s a quick update of what we’ve been seeing, starting with news from the recent SOI Consortium forum in Tokyo. Many of the presentations are now available on the SOI Consortium website – but keep checking back for more.
Samsung: 28nm FD-SOI hits maturity, mass production starts 1Q2016
Yongjoo Jeon, Principal Engineer in SEC Foundry marketing, Samsung, gave a talk entitled, The industry’s first mass-produced FDSOI technology for the IoT era, with single design platform benefits.
Here are his key messages with respect to 28nm FD-SOI:
For other key Samsung slides showing data on their success in manufacturability, check out EETimes.
GlobalFoundries: RF-SOI for 5G, FD-SOI Customers Engaged
Subramani Kengeri, VP of Global Design Solutions at GlobalFoundries talked about their 22nm FD-SOI, in his presentation Enabling SoC Innovations with 22FDXTM. He indicated that they’ve got over 40 customers engaged on it. Key points they’re hitting on that make them bullish on their prospects include:
For more on how GF see 22FDX as very well-positioned for IoT, see their Foundry Files blog. There’s also a really good piece in EEJournal by Byron Moyer entitled, A Non-FinFET Path to 10 nm – GlobalFoundries’ FD-SOI Alternative.
GF is of course also a dominant RF-SOI player, as seen in RFSOI: Defining the RF-Digital Boundary for 5G by Peter Rabbeni, Sr. Director RF Product Marketing and Business Development, GlobalFoundries. The presentation, which is available on the SOI Consortium website, notes that, “Significant R&D has been done in evaluating the application of SOI to 5G architectures, with very positive results,” so that, “SOI holds great promise in delivering on the key requirements of 5G systems.” (For an overview of GF’s RF-SOI position, see RF-SOI is IoT’s Future, and the Future in Bright on their Foundry Files blog.)
Renesas: in FD-SOI production at 65nm this year
Shiro Kamohara, Chief Engineer, Renesas Electronics Corp., lead off the presentations with Ultralow-Voltage Design and Technology of Silicon-on-Thin-Buried-Oxide (SOTB) CMOS for Highly Energy Efficient Electronics in IoT Era.
A Nikkei article reported from the conference that Renesas will be in mass production of 65nm FD-SOI – which they call Silicon-on-Thin-Box, or SOTB – for IoT products this year. Renesas reports the move cuts power to a tenth of what they’d seen in bulk. You can see the original article in Japanese here or a translated version here.
Soitec: wafers ready for mass adoption
In the presentation Substrate maturity and readiness in large volume to support mass adoption of ULP FDSOI platforms, Soitec Sr. VP of Digital Electronics Group Christophe Maleville, Senior Vice President, Digital Electronics BU provided data on every conceivable aspect of SOI wafers for FD-SOI and RF-SOI. He explained adaptations in the company’s Smart CutTM manufacturing technology that achieve astonishing levels of uniformity and thickness – or rather, thinness! With new metrology, they can predict and protect against variability in devices. And they are now producing FD-SOI wafers for 28nm processes with uniformity of +/- 1 atomic layer.
ST: making the case
For analog/RF, RF/mmW and mixed-signal/high-speed designers, Andreia Cathelin, Senior Member of Technical Staff at STMicroelectronics explained how and why FD-SOI makes their lives easier. Her presentation, FDSOI Technology Advantages for Analog/RF and Mixed-Signal Designs drills down to the technical for these folks.
Pietro Maestri, ST’s RF Product Line Director presented ST H9SOI_FEM: 0.13µm RF-SOI Technology for Front End Module Integration. (BTW, we had an excellent high-level article by ST when H9SOI_FEM was first announced, describing the challenges faced by designers of smartphone front-end modules (FEMs) and how their H9SOI_FEM solves them – read it here.)
For anyone wondering about the status of FD-SOI following the just-announced company reorganization, COO Jean-Marc Chery told EETimes’ Peter Clarke that they remain fully committed to the technology. As noted in the article (read the whole thing here), “Chery emphasized that, following the announcement of ST’s withdrawal from STB and home gateway markets and of a proposed redeployment of 600 engineers, the company is now focused on automotive and Internet of Things applications and that therefore FDSOI is a core manufacturing process. Indeed it could be argued that moving engineers familiar with FDSOI from the STB group into MCUs and automotive will help to proliferate the technology through the company.”
NXP/Freescale: Loving FD-SOI
In another recent EETimes article, Peter Clark reported from the NXP “Smarter World Tour” that the newly merged NXP-Freescale is very bullish on FD-SOI (see the full article here).
He cites Goeff Lees, the GM for the MCU part of the merged businesses, who especially likes 28nm FD-SOI for IoT and MCUs. Ticking off the reasons, he lists energy efficiency, cost, analog support, security, temperature control and lower leakage current. In fact, he says, “I believe all MCU vendors could move to FD-SOI.” Wow.
So stay tuned – here at ASN we’ve got contributions from NXP/Freescale, Synopsys, GlobalFoundries, Surecore and more at the top of the 2016 queue. Yes, it’s going to be a good year.
For this 3-part series, ASN spoke with Kelvin Low, senior director of marketing for Samsung Foundry and Axel Fischer, director of Samsung System LSI business in Europe about the company’s FD-SOI offering. Here in part 3, we’ll talk about the ecosystem. (In part 1 we talked about technology readiness, and in part 2, we talked about design.)
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ASN: Let’s talk a little more about IP availability.
Axel Fischer: The availability of IP is key for engaging these market segments. The technology itself is ready. The gating item often is the IP element.
Kelvin Low: The IP element is broadly ready. But we’re not stopping there. We’re enhancing the IP and adding on new suppliers. Most of them we can’t name yet just because of timing. But we can confidently say that multiple new IP suppliers are coming online, and many more have started to inquire about how they can get onboard.
ASN: In terms of the ecosystem, what remains to be done?
KL: The ecosystem can never end. Enhancements will always be welcome. More support – there are so many other EDA software companies out there available. We will enable them if there is a customer behind them. IP are dictated by the standards. As long as the product requires that, we’ll continue to look for partners to develop the IP.
KL: Back to one of the strategic decisions we made. We have immediately made available what ST Micro has in terms of IP portfolio to our customers. Then continuously build this ecosystem according to the new customers that we’re acquiring. ST Micro has developed these IPs for their own internal products, and they were gracious enough to allow these IPs to be opened up to be used by all customers without restriction.
As a group, as an ecosystem, we have to be more proactive in educating the market. What we’ve seen so far, whether it’s an initiative by Leti or an initiative by the SOI Consortium, these are very helpful. Now you have so many more knobs that you can play with, for designers we have to prepare all these PVT – which is process, voltage, temperature, and timing points so they can actually use it. It’s just a matter of preparation needed from our end, working with the ecosystem. The EDA tools must be optimized to make it as seamless, as transparent as possible.
ASN: Any closing thoughts?
KL: 28FDSOI is real. Samsung is committed. The technology is qualified already. The ecosystem is ready and expanding. This is working stuff. It’s not a powerpoint technology.
This is the last installment in ASN’s 3-part interview with Samsung on their 28nm FD-SOI foundry offering. If you missed the other parts, you can still read part 1 about technology readiness (click here), and part 2 on design considerations (click here).
For this 3-part series, ASN spoke with Kelvin Low, senior director of marketing for Samsung Foundry and Axel Fischer, director of Samsung System LSI business in Europe about the company’s FD-SOI offering. Here in part 2, we’ll talk about design. (In part 1, we talked about Samsung’s technology readiness. In part 3, we’ll talk about the ecosystem.)
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ASN: Let’s start by talking about value. What do you see as the key advantages of 28nm FD-SOI?
Kelvin Low: FD-SOI is wide-ranging. What I mean by this is for the designers, there are many design knobs available that you can use to achieve either high performance or ultra low power. That’s a an extremely valuable and important proposition. The wide dynamic performance-power range is achieved with FD-SOI’s body biasing ability. Though bulk technologies allow body biasing, it has a comparatively much narrower range.
Another key benefit is the super analog gain and properties of FD-SOI. I think moving forward, we’ll probably start to see more customers that are analog-centric. Later on, we’ll see this as one of the key value propositions of FD-SOI. Today, there’s still a lot of digital customers that we’re engaged with right now. The analog customers are still not yet aggressively migrating to [[more advanced]] technology nodes, but when they come, this will be an important distinction in FD-SOI vs. bulk.
Another important distinction not related to power-performance-area is the robustness of the reliability. This is a well-proven fact that FD-SOI is much more robust for soft-error immunity as compare to bulk. So anything that needs radiation protection (for example, military, aerospace – but those are not really the high-volumes), as well as automotive products, you’ll see value of better SER immunity as compared to bulk. Not just memory SER but logic SER. There are available design techniques to overcome / account for that. For example, if you design to overcome SER, you incur overhead in area for example. With FD-SOI, this is intrinsic, so you don’t need design tricks to suppress it.
ASN: When should designers consider using 28nm FD-SOI as opposed moving to 14nm FinFET or choosing another 28nm technology?
KL: By virtue of one being 28 and the other being 14, if you do need a lot of logic feature integration, or die-size reduction, 14nm will obviously become more necessary. If you just are looking for power savings, both 14nm FinFET and 28nm FD-SOI are fully depleted in nature, so both are able to operate with a lower power supply. So those are similarities. 14nm FinFET does provide higher performance compared to 28nm by virtue of how the process is constructed. Lastly, cost, which is related to the number of double-patterning layers – at 28nm, avoiding all the expensive double-patterning layers and 14nm having double-patterning being necessary for all the area scaling – that presents itself as a real difference. The end-product cost can also determine the choice of the technology selection.
Axel Fischer: The end-product cost, plus as well the investments from the customer side: the customer has to make a certain investment to develop the chip in terms of overall cost. If you look at photomask payment, NRE* and so on – this is weighting strongly, more and more as you go forward with advanced node technologies. There’s a set of customers that are feeling very comfortable to stay on the 28nm node.
KL: There are several 28nm flavors. There’s Poly-SiON, there’s HKMG, and there’s HKMG-FD-SOI. In terms of performance, there’s really a very clear distinction. In terms of power, you see a more radical power reduction with FD-SOI. In chip area scaling, I’d say roughly the same between HKMG and FD-SOI. This is dictated not so much by the transistor but by the overall design rules of the technology. So, 14nm is the higher cost point. 28nm is a much lower cost point, so overall a given budget that a customer has can determine whether 14nm is usable or otherwise. We have to sit down with the customer and really understand their needs. It’s not just trying to push one over the other solution. Based on their needs, we’ll make the proper recommendations.
ASN: Can designers get started today?
KL: We are moving FD-SOI discussions with customers to the next phase, which is to emphasize the design ecosystem readiness. So what we’ve been working on, and we really appreciate ST Micro’s support here, is to kick-start market adoption. We have access to ST Micro’s foundation library, and some of their foundation and basic IPs. Here, Samsung is distributing and supporting customers directly. They need to only work with us, and not with ST Micro. So they have access to the IP through us. We also provide design support, and we have additional IPs coming in to serve the customers from the traditional IP providers.
Many designers are new to body biasing. Fortunately, there are a couple of design partners that can help in this area. Synapse being one of them; Verisilicon another. Already, they have put in resources and plans and additional solutions to catalyze this market. In short, the PDK is available today, and the PDK supporting multi tools – Synopsys, Cadence and Mentor – are all available for download today. Libraries are also all available for download.
There’s nothing impeding designers from starting projects now. This is why we believe that 28FDSOI is the right node, because we are enabling the market to start projects today. If we start something else down the road, like a 14nm FD-SOI, for example, or something in between, the market will just say, hey, we like your transistor, we like your slides, but I have nothing to start my project on. So that is bad, because then it becomes a vicious cycle. We believe we have to enable 28nm designs now. Enable customers to bring actual products to the market. Eventually from there you can evolve 28 to something else.
ASN: Let’s talk some more about design considerations and body biasing, how it’s used and when.
KL: Both 14nm FinFET and 28nm FD-SOI are fully depleted. One unique technology value of fully-depleted architecture is the ability to operate the device at lower power supply. So power is the product of CV²/frequency. If you can operate this chip at lower power supply, you get significant dynamic power savings. FinFET does not have a body effect, so you cannot implement body biasing – it’s just not possible.
FD-SOI, on the other hand, has this extra knob – body biasing – that you can use. With reverse body bias (RBB), you can get much lower leakage power. If you want more performance, you can activate the FBB to get the necessary speed. Again, this is not possible with FinFET. So that will be one distinction. It depends on how you’re using your chip. It all depends on the system side, or even at the architecture side, how is it being considered already. If you’re already very comfortable using body biasing, then going to FinFET is a problem, because you’ve lost a knob. Some would rather not lose this knob because they see it as a huge advantage. That doesn’t mean you can’t design around it, it’s just different.
There are already users of body biasing for bulk. For customers that already use body biasing, this is nothing new. They’re pleased to now have the wider range, as opposed to the more narrow range for bulk.
AF: And probably going to FinFET is more disruptive for them. With FinFET, you have double-patterning considerations, etc. More capacitance to deal with.
ASN: Porting – does FD-SOI change the amount of time you have to budget for your port?
KL: If a customer already has products at 28nm, and they’re now planning the next product that has higher speed or better power consumption – they’re considering FinFET as one option, and now maybe the other option available is 28nm FD-SOI. The design learnings of going to FinFET are much more. So the port time will be longer than going to 28nm FD-SOI. We see customers hugely attracted because of this fact. Now they’re trying to make a choice. If it’s just a time-to-market constraint, sometimes FinFET doesn’t allow you to achieve that. If you have to tape out production in six months, you may have to use FD-SOI.
AF: Another key point for customers deciding to work with 28FDSOI is the fact that Samsung Foundry has joined the club. A few customers really hesitated on making the move to 28nm FD-SOI ST Micro is a very really advanced company, doing its own research and development, but the fact that the production capability was very limited has people shying away. Besides the technology, the presence and the engagement of Samsung is giving another boost to the acceptance.
KL: Yes, we’re recognized as a credible, high-volume manufacturing partner. That helps a lot.
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*NRE = non-recurring engineering. In a fabless scenario, there are NRE for IP and design (engineering costs, up-front and royalty-based IP costs), NRE for masks and fabrication (mask costs, wafer prototype lots, tools costs, probe cards, loadboards and other one-time capital expenditures), and NRE for qualifications (ESD, latch-up and other industry-specific qualifications, as in automotives).
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This is the second installment in ASN’s 3-part interview with Samsung on their 28nm FD-SOI foundry offering. If you missed the other parts, you can still read part 1 about technology readiness (click here), and part 3 on the ecosystem (click here).
ASN spoke with Kelvin Low, senior director of marketing for Samsung Foundry and Axel Fischer, director of Samsung System LSI business in Europe about the company’s FD-SOI offering. Here in part 1, we’ll talk about technology readiness. In parts 2 and 3, we’ll talk about design and the ecosystem.
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ASN: Where does Samsung stand in terms of rolling out your 28nm FD-SOI offer?
Kelvin Low: We have completed key milestones. Wafer level qualification was completed in September 2014, and then product level qualification in March 2015. So, the good news is the technology is fully qualified now.
What we have additionally in terms of overall technology readiness is production PDKs available right now. We have run a couple of MPWs already, and we’re scheduling more for next year. Silicon is really running in our fab. I think many may not have grasped that fact. Silicon is running, and we are running production for ST as one of our lead customers.
Axel Fischer: We already have a long relationship with ST – since 32 and 28nm HKMG bulk. We had a press release where we stated that more than a dozen projects had been taped out. EETimes published an article at the time. Adding 28 FD-SOI was a natural extension of an existing relationship
KL: That’s right –This is not a new customer scenario – it’s an existing customer, but an expansion of technology. And, in this case, it’s also a collaboration technology and IP solutions.
We are ST Micro’s primary manufacturing partner; this is one reason that it’s mutually beneficial for both of us. Crolles is not aiming for high volume. They prototype well. They do MPW and IP well, but they are not a high-volume fab. So, we complete the production rollout at Samsung Foundry.
ASN: Do you have other customers lined up?
KL: The short answer is yes. Beyond ST, Freescale can we talk about, since they have openly stated that they are using FD-SOI with us. Other customers, unfortunately, we just can’t say.But, they are in all the market segments (especially IoT) where the cost and ultra-low power combination is a very powerful one.
ASN: What about technology readiness and maturity?
KL: We have a couple of different 28 variants: the LPP, the LPH with more than a million wafers shipped. And because of that, our D0 – defect density – is at a very mature level. 28FD-SOI, sharing almost 75% of the process modules of 28 bulk, allows us to go to a very steep D0 reduction curve. We are essentially leveraging what we already know from the 28 bulk production experience. Defect density is essentially the inverse of yield. So, the lower the D0, the higher the yield.
This slide [[see above]] show the similarities between our FD-SOI and our 28 HKMG bulk. You can see how more than 75% of bulk modules are reused. The BEOL is identical, so its 100% reused. On the FEOL, some areas require some minor tuning and some minor modification, but anything that is specific to FD-SOI is less than 5% that we have to update from the fab perspective. All the equipment can be reused in the fab. There may be a couple of pieces related to the FD-SOI process that need to be introduced.Other than that, the equipment is being reused and can depreciated,.which is essential for any business. We leverage another lifetime for the tools.
ASN: When will we see the first high-volume FD-SOI chips? Next year?
KL: It depends on what market segment. Consumer, yes, I fully agree, they can ramp very fast. But other segments like infrastructure, networking or automotive, they’ll take a longer time to just qualify products.
AF: It’s not just us. If our customer needs to prove that the product is compliant with certain standards, you have to go through test labs and so on, this can be a very lengthy process. Product can actually be ready, and we’re all waiting to produce, but they’re still waiting for reports and the software that’s goes on top – this can be a very long cycle.
KL: We’re already starting to support the production ramp for ST. They’ll be on the market very soon.
[[Editor’s note: ST has announced three set-top box chips on 28nm FD-SOI– you can read about them here.]]
KL: Everyone’s waiting for ChipWorks or TechInsights to cut away an end-product device that has FD-SOI. It’s just a matter of time.
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From wafers to apps, Leti has been the moving force behind all things SOI for over 30 years. Now they’re the powerhouse behind the FD-SOI phenomenon. CEO Marie-Noelle Semeria shares her insights here in part 2 of this exclusive ASN interview as to what Leti’s doing to drive the ecosystem forward. (In part 1, she shared her insights into what makes Leti tick – if you missed it, you can click here to read it now.)
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ASN: In which areas do you see SOI giving designers an edge?
MS: There is an advantage in terms of cost and power, so it’s attractive for IoT, for automotive, and more and more for medical devices. We see the first products in networks, in imaging, in RF. The flexibility of the design, thanks to the back bias gives another asset in terms of integration and cost. We consider that 28nm FD-SOI and 22nm FD-SOI are the IoT platforms, enabling many functions required by IoT applications. It’s a very exciting period for designers, for product managers, for start-ups. You can imagine new applications, new designs, and take advantage of engineered substrates combined with planar FD-SOI CMOS technology and 3D integration strategies to explore new frontiers.
ASN: What is Leti doing moving forward?
MS: Our commitment is to create value for our partners. So what is key for SOI now is to extend the ecosystem and to catch the IoT wave, especially for automotives, manufacturing and wearables. That’s why we launched the Silicon Impulse Initiative (SII) as a single entry gate providing access to FD-SOI IP and technology. SII is a consortium, gathering Soitec, ST, CMP, Dolphin and others, in order to beef up the EDA and design ecosystems. Silicon Impulse offers multi-project wafer runs (MPWs) with ST and GF as foundries based on a full portfolio of IPs. SII is setting up the ecosystem to make FD-SOI technology available for all the designers who have IP in bulk or in FinFET. To reach designers, we have set up events close to international conferences like DAC and VLSI, and we promote SII together with the SOI Consortium in San Francisco, Taiwan, Shanghai, Dresden….
The second way we are accelerating the deployment of FD-SOI technology in manufacturing is to provide our expertise to the companies who made the choice for FD-SOI technology. Leti assignees are working in Crolles with ST and in Dresden with GF to support the development of the technology and of specific IP such as back bias IP. The design center located in the Minatec premises is also open to designers who want to experiment with FD-SOI technology and have access to proof in silicon.
ASN: What role does Leti play in the SOI roadmap?
MS: The role of Leti is to pioneer the technology, to extend the ecosystem and to demonstrate in products the powerful ability of FD-SOI to impact new applications. Leti pioneered FD-SOI technology about 20 years ago. Soitec is a start-up of Leti, as well as SOISIC (which was acquired by ARM) in design. We developed the technology with ST, partnering with IBM, TI and universities. Now we’ve opened the ecosystem with GlobalFoundries and are considering new players. With the Silicon Impulse Initiative we are going a step further to open the technology to designers in the framework of our design center. We have had a pioneering role. Now we have to play a catalyst role in order to channel new customers toward FD-SOI technology and to enable new products.
Leti demonstrates that the FD-SOI roadmap can be expanded up to 7nm with huge performance taking advantage of the back biasing. Leti’s role is to transform the present window into a wide route for numerous applications requiring multi-node generations of technologies.
ASN: Is Silicon Impulse strictly FD-SOI, or do you have photonics, MEMS, RF-SOI…?
MS: We started with FD-SOI at 28nm because it’s available: it’s here. But as soon as the full EDA-IP ecosystem is set-up, this will be open for sure to all the emerging technologies: embedded memory (RRAM, PCM,MRAM…), 3D integration (CoolCube, Cu/Cu), imaging, photonics, sensors, RF, neuromorphic technology, quantum systems….which are developed in Leti. Having access to a full capability of demonstrations in a world class innovation ecosystem backed by a semiconductor foundry and a global IP portfolio leverages the value of SII.
ASN: Can you tell us about the arrangement with GlobalFoundries for 22nm FD-SOI? How did that evolve, and what does it mean for the ecosystem?
MS: Yes, last month we announced that we have joined GlobalFoundries’ GlobalSolutions ecosystem as an ASIC provider, specifically to support their 22FDX™ technology platform. We have worked with GlobalFoundries over the years in the frame of the IBM Alliance pre-T0 program..
In joining the GlobalSolutions ecosystem, Leti’s goal is to ensure that GF’s customers – chip designers – get the very best service from FD-SOI design conception through high-volume production. This has been in the works for a while. At the beginning of 2015, we sent a team to GlobalFoundries’ Fab 1 in Dresden to support ramp up of the platform. And now as an ecosystem partner, Leti will help their customers with circuit-design IP, including fully leveraging the back-bias feature, which will give them exceptional performance at very low voltages with low leakage.
We will be able to help a broad range of designers use all the strengths that FD-SOI brings to the table in terms of ultra-low-power and high performance, especially in 22nm IoT and mobile devices. It really is a win-win situation, in that both our customer bases will get increased access to both our respective technologies and expertise. It’s an excellent example of Leti’s global strategy.
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(This concludes part 2 of 2 in this Leti interview series. In part 1, Marie Semeria shared her insights into what makes Leti tick – if you missed it, you can click here to read it now.)
CEA-Leti has signed an agreement with Keysight Technologies (formerly the Agilent/HP test group), the industry-leading device-modeling software supplier, to adopt Leti’s UTSOI extraction flow methodology within Keysight’s device modeling solutions for high-volume SPICE model generation. (Read the press release here.)
“This collaboration between Leti and Keysight will strengthen the global FD-SOI ecosystem by providing an automatic extraction flow for building model cards associated with the Leti-UTSOI models, which are already available in all the major SPICE simulators,” said Marie Semeria, Leti’s CEO. “This professional, automatic extraction-flow solution will address designers’ needs as they weigh FD-SOI’s benefits over competing solutions for the 28nm technology node and below.”
Compact models of transistors and other elementary devices are used to predict the behavior of a design. As such, they are embedded in simulations like SPICE that designers run before actual manufacturing. Power optimization is of course a key component in SOC design. Automatic extraction helps ensure that the power intent specified by the designer in the simulated transistors will really match what will ultimately be seen in silicon.
The simulation of the Leti-UTSOI compact model, which is the first complete compact model dedicated to Ultra-Thin Body and Box and Independent Double Gate MOSFETs (aka FD-SOI), is currently available in Keysight’s modeling and simulation tools. This agreement expands the collaboration to include the extraction flow and will enable device-modeling engineers to efficiently create Leti-UTSOI model cards for use in Process Design Kits (PDKs).
Over the last few weeks there’s been another burst of activity in the FD-SOI arena. A new round of articles, videos and conferences are making FD-SOI the centerpieces. Here’s a quick round-up of things you won’t want to miss.
Info on GlobalFoundries 22nm FD-SOI offering just keeps on coming. Following the ASN roundup of info from the summer and fall (missed it? read it here), they’ve posted yet another excellent FD-SOI video:
How to optimize power and performance with 22FDX™ Platform body-biasing – Dr. Jamie Schaeffer gives a quick (under 3 minute) guide to the basics of front and reverse body-biasing, and the GF approach to a dynamic trade-off between power and performance . He explains how forward body bias (FBB) boosts performance at both high and low voltages, and how reverse body bias (RBB) cuts leakage for the lowest standby power. He also touches on FBB techniques for analog/RF designs.
They’re back! Though they’ve been pretty quiet recently, this latest Samsung video on their 28nm FD-SOI foundry offering hits right at the heart of IoT. Entitled The IoT Revolution and Samsung Foundry’s 28nm FD-SOI, the fun two-minute spot features two runners talking shop during a break. She asks: Is there a lot of design ecosystem support for FD-SOI? He answers: Absolutely. And he goes on to talk about the EDA/IP ecosystem they’re building. It ends on this tantalizing note: He: So you’re done? She: Not! Race you to the next station! He: Oh, it’s on!
With reader interest high and higher, FD-SOI continues to get great coverage in SemiWiki.com. Here are some recent good reads:
IP-SoC Rebound in 2015 ! – IP expert Eric Esteve covers FD-SOI highlights from the upcoming IP-SOC 2015 conference in Grenoble, France (2-3 December 2015), including these presentations (full program here):
28nm FD-SOI: A Unique Sweet Spot Poised to Grow – Pawan Fangaria explains why “…today the 28nm FD-SOI technology node stands to win as the best value added proposition for the emerging markets such as IoT, automotive, consumer, mobile, and so on.”
Globalfoundries 22FDX Technology Shows Advantages in PPA over 28nm Node – Tom Simon was at ARM Techcon, where he attended a talk sponsored by Cadence on the topic of using GlobalFoundries 22nm FD-SOI process to implement a quad core ARM Cortex-A17. He shares a number of the key slides in this informative blog.
SemiEngineering Editor-in-Chief Ed Sperling continues his great line-up of incisive interviews. In Increasing Challenges At Advanced Nodes, he gets some spot-on FD-SOI quotes from GlobalFoundries CTO Gary Patton, including: