Future Horizons hosted the 22nd Annual International Electronics Forum, in association with IDA Ireland, on Oct. 2-4, 2013, at Dublin, Blanchardstown, Ireland. The forum was titled ‘New Markets and Opportunities in the Sub-20nm Era: Business as Usual OR It’s Different This Time.” Here are excerpts from some of the sessions. Those desirous of finding out much more should contact Malcolm Penn, CEO, Future Horizons.
The global interest in graphene research has facilitated our understanding of this rather unique material. However, the transition from the laboratory to factory has hit some challenging obstacles. In this talk I will review the current state of graphene research, focusing on the techniques which allow large scale production.
I will then discuss various aspects of our research which is based on more complex structures beyond graphene. Firstly, hexagonal boron nitride can be used as a thin dielectric material where electrons can tunnel through. Secondly, graphene-boron nitride stacks can be used as tunnelling transistor devices with promising characteristics. The same devices show interesting physics, for example, negative differential conductivity can be found at higher biases. Finally, graphene stacked with thin semiconducting layers which show promising results in photodetection.
I will conclude by speculating the fields where graphene may realistically find applications and discuss the role of the National Graphene Institute in commercializing graphene.
The key challenge for future high-end computing chips is energy efficiency in addition to traditional challenges such as yield/cost, static power, data transfer. In 2020, in order to maintain at an acceptable level the overall power consumption of all the computing systems, a gain in term of power efficiency of 1000 will be required.
To reach this objective, we need to work not only at process and technology level, but to propose disruptive multi-processor SoC architecture and to make some major evolutions on software and on the development of
applications. Some key semiconductor technologies will definitely play a key role such as: low power CMOS technologies, 3D stacking, silicon photonics and embedded non-volatile memory.
To reach this goal, the involvement of semiconductor industries will be necessary and a new ecosystem has to be put in place for establishing stronger partnerships between the semiconductor industry (IDM, foundry), IP provider, EDA provider, design house, systems and software industries.
This presentation looks at the development of the semiconductor and electronics industries from an African perspective, both globally and in Africa. Understanding the challenges that are associated with the wide scale adoption of new electronics in the African continent.
Electronics have taken over the world, and it is unthinkable in today’s modern life to operate without utilising some form of electronics on a daily basis. Similarly, in Africa the development and adoption of electronics and utilisation of semiconductors have grown exponentially. This growth on the African continent was due to the rapid uptake of mobile communications. However, this has placed in stark relief the challenges facing increased adoption of electronics in Africa, namely power consumption.
This background is central to the thesis that the industry needs to look at addressing the twin challenges of low powered and low cost devices. In Africa there are limits to the ability to frequently and consistently charge or keep electronics connected to a reliable electricity grid. Therefore, the current advances in electronics has resulted in the power industry being the biggest beneficiary of the growth in the adoption of electronics.
What needs to be done is for the industry to support and foster research on this subject in Africa, working as a global community. The challenge is creating electronics that meet these cost and power challenges. Importantly, the solution needs to be driven by the semiconductor industry not the power industry. Focus is to be placed on operating in an off-grid environment and building sustainable solutions to the continued challenge of the absence of reliable and available power.
It is my contention that Africa, as it has done with the mobile communications industry and adoption of LED lighting, will leapfrog in terms of developing and adopting low powered and cost effective electronics.
Personalized, preventive, predictive and participatory healthcare is on the horizon. Many nano-electronics research groups have entered the quest for more efficient health care in their mission statement. Electronic systems are proposed to assist in ambulatory monitoring of socalled ‘markers’ for wellness and health.
New life science tools deliver the prospect of personal diagnostics and therapy in e.g., the cardiac, neurological and oncology field. Early diagnose, detailed and fast screening technology and companioning devices to deliver the evidence of therapy effectiveness could indeed stir a – desperately needed – healthcare revolution. This talk addresses the exciting trends in ‘PPPP’ health care and relates them to an innovation roadmap in process technology, electronic circuits and system concepts.
San Jose, USA-based Atrenta’s SpyGlass Predictive Analyzer gives engineers a powerful guidance dashboard that enables efficient verification and optimization of SoC designs early, before expensive and time-consuming traditional EDA tools are deployed. I recently met up with Dr. Ajoy Bose, chairman, president and CEO, Atrenta, to find out more.
I started by asking how Atrenta provides early design analysis for logic designers? He said: “The key ingredient is something we call predictive analysis. That is, we need to analyze a design at a high level of abstraction and predict what will happen when it undergoes detailed implementation. We have a rich library of algorithms that provide highly accurate ‘predictions’, without the time and cost required to actually send a design through detailed implementation.”
There’s a saying: electronic system level (ESL) is where the future of EDA lies. Why? Its because the lower level of abstraction (detailed implementation) of the EDA market is undergoing commoditization and consolidation. There are fewer solutions, and less differentiation between them. At the upper levels of abstraction (ESL), this is not the case. There still exists ample opportunity to provide new and innovative solutions.
Now, how will this help EDA to move up the embedded software space? According to Dr. Bose, the ability to do true hardware/software co-design is still not a solved problem. Once viable solutions are developed, then EDA will be able to sell to the embedded software engineer. This will be a new market, and new revenue for EDA.
How are SpyGlass and GenSys platforms helping the industry? What problems are those solving? Dr. Ajoy Bose said: “SpyGlass is Atrenta’s platform for RTL signoff. It is used by virtually all SoC design teams to ensure the power, performance and cost of their SoC is as good as it can be prior to handoff to detailed implementation.SpyGlass is also used to select and qualify semiconductor IP – a major challenge for all SoC design teams.
“GenSys provides a way to easily assemble and modify designs at the RTL level of abstraction. As a lot of each SoC is re-used design data, the need to modify this data to fit the new design is very prevalent. GenSys provides an easy, correct-by-construction way to get this job done.”
How does the SpyGlass solve RTL design issues, ensuring high quality RTL with fewer design bugs? He added that it’s the predictive analysis technology. SpyGlass provides accurate and relevant information about what will happen when a design is implemented and tested. By fixing these problems early, at RTL, a much higher quality design is handed off to detailed implementation with fewer bugs and associated schedule challenges.
On another note, I asked him why Apple’s choice of chips a factor in influencing the global chip industry? The primary reason is their volume and buying power. Apple is something of a “King Maker” when it comes to who manufactures their chips. Apple is also a thought leader and trend setter, so their decisions affect the decisions of others.
Finally, the global semiconductor industry! How is the global semicon industry doing in H1-2013? As per Dr. Bose: “We see strong growth. Our customers are undertaking many new designs at advanced process technology nodes. We think that this speaks well for future growth of the industry. At a macro level, the consumer sector will drive a lot of the growth ahead. For EDA, the higher levels of abstraction is where the growth will be.”
POET Technologies Inc., based in Storrs Mansfield, Connecticut, USA, and formerly, OPEL Technologies Inc., is the developer of an integrated circuit platform that will power the next wave of innovation in integrated circuits, by combining electronics and optics onto a single chip for massive improvements in size, power, speed and cost.
POET’s current IP portfolio includes more than 34 patents and seven pending. POET’s core principles have been in development by director and chief scientist, Dr. Geoff Taylor, and his team at the University of Connecticut for the past 18 years, and are now nearing readiness for commercialization opportunities. It recently managed to successfully integrate optics and electronics onto one monolithic chip.
Elaborating, Dr. Geoff Taylor, said: “POET stands for Planar Opto Electronic Technology. The POET platform is a patented semiconductor fabrication process, which provides integrated circuit devices containing both electronic and optical elements on a single chip. This has significant advantages over today’s solutions in terms of density, reliability and power, at a lower cost.
“POET removes the need for retooling, while providing lower costs, power savings and increased reliability. For example, an optoelectronic device using POET technology can achieve estimated cost savings back to the manufacturer of 80 percent compared to the hybrid silicon devices that are widely used today.
“The POET platform is a flexible one that can be applied to virtually any market, including memory, digital/mobile, sensor/laser and electro-optical, among many others. The platform uses two compounds – gallium and arsenide – that will allow semiconductor manufacturers to make microchips that are faster and more energy efficient than current silicon devices, and less expensive to produce.
“The core POET research and development team has spent more than 20 years on components of the platform, including 32 patents (and six patents pending).”
Moore’s Law to end next decade?
Is silicon dead and how much more there is to Moore’s Law?
According to Dr. Taylor, POET Technologies’ view is that Moore’s Law could come to an end within the next decade, particularly as semiconductor companies have recently highlighted difficulties in transitioning to the next generation of chipsets, or can only see two to three generations ahead.
Transistor density and its impact on product cost has been the traditional guideline for advancing computer technology because density has been accomplished by device shrinkage translating to performance improvement. Moore’s Law begins to fail when performance improvement translates less and less to device shrinkage – and this is occurring now at an increasing rate.
He added: “For POET Technologies, however, the question to answer is not when Moore’s Law will end – but what next. Rather than focus on how many more years we can expect Moore’s Law to last – or pinpoint a specific stumbling block to achieving the next generation of chipsets, POET looks at the opportunities for new developments and solutions to continue advancements in computing.
“So, for POET Technologies, we’re focusing less on existing integrated circuit materials and processes and more towards a different track with significant future runway. Our platform is a patented semiconductor fabrication process, which concentrates on delivering increases in performance at lower cost – and meets ongoing consumer appetites for faster, smaller and more power efficient computing.”
300mm is the new 200mm, said GlobalFoundries’ David Duke, during a presentation titled ‘Used Equipment Market’ at the recently held Semicon West 2013 in San Francisco, USA. Used semiconductor equipment sourcing and sales is a very interesting challenge.
Qimonda, Spansion, Powerchip and ProMOS had jumpstarted the market. Now, there is a broadening user base. There is an unexpected uptake by analog and power device producers to achieve economies of scale. There has been legacy logic scaling. Also, the 200mm fabs are being upgraded to 300mm with used equipment. Many 300mm tools can “bridge” to 200mm easily.
Parts tools are seeding the ecosystem. Third parties are also able to support refurb as well as tool moves. However, we need more! Software licensing is becoming a smaller hurdle. There has been no over-supply yet!
So, what are the ‘rough’ rules of thumb for 300mm? First, there are approximately 1,500 individual tools in the open market. Few sellers know the values as the market is still developing. Twenty percent of the transactions drive 80 percent of sales. Today, the number of 300mm buyers is around 1/10th the number of 200mm buyers!
Lithography has been the biggest difference. Leading edge DRAM is far more expensive in lithography. Lithography has seen the most dramatic financial effects with explosive pricing in technology (immersion) and the need for capacity (two-three critical passes vs. one with dual/triple gate patterning. As of now, financial shocks and bankruptcies are the main drivers for used 300mm.
Next, 200mm is now the new 150mm! The 200mm OEM support is starting to dry up. It is nearly impossible to compete in productivity vs. 300mm. Oversupply is causing values to stay suppressed. The only bright spot being: there is still strong demand for complete fabs. The 200mm market split is roughly by 40 percent Asia and 60 percent rest of the world.
So, what are the likely alternative markets for 200mm and 300mm fabs? These are said to be MEMs and TSV, LEDs and solar PV.
That brings me to India! What are they doing about fabs over here? This article has enough pointers as to what should be done. Otherwise, the world is already moving to 450mm fabs! Am I right?
Xilinx Inc. has taped-out the first 20nm All Programmable Device with first UltraScale ASIC-class programmable architecture. It is said to be the semiconductor industry’s first 20nm device, and the PLD industry’s first 20nm All Programmable device. Xilinx implemented the industry’s first ASIC-class programmable architecture called UltraScale.
These milestones expand on Xilinx’s industry first 28nm tape-out, All Programmable SoCs, All Programmable 3D ICs, and SoC-strength design suite. Xilinx already has several firsts in the 28nm space, such as:
* First 28nm tape-out.
* First All Programmable SoC.
* First All Programmable 3D IC.
* First SoC-strength design suite.
Neeraj Varma, director-Sales, India, said that Xilinx’s global market share in the 28nm portfolio was 65 percent in March 2013. With the launch of the industry’s first 20nm All Programmable Device with first UltraScale ASIC-class programmable architecture, there are improvements such as 1.5-2x performance and integration, and a year ahead of the competition. It handles massive I/O bandwidth, massive memory bandwidth, massive data flow and routing, and fastest DSP processing. The architecture will scale — from monolithic to 3D IC, planar to FinFET, and ASIC-class performance.
The UltraSCALE architecture points to high performance smarter systems. For example, 1Tps in OTN networking, 8K in digital video, LTE-A in wireless communications, and digital array in radar. There will be requirements for massive packet processing over 400 Gbps wire-speed, massive data flow over 5Tbps, as well as massive I/O and memory bandwidth over 5Tbps, and DSP performance over 7 TMACs.
The mandate for ASIC-class programmable architecture is to remove bottlenecks for massive data flow and smart processing, high throughput with low latency, and efficient design closure with greater than 90 percent utilization without performance degradation. These are the benefits of applying leading edge ASIC techniques in a fully programmable architecture.
ASIC-like clocking maximizes performance margin for highest throughput. UltraSCALE ASIC-like clocking enables clock placement virtually anywhere on the die, making the clock skew problem go away. Also, highly optimized critical paths remove bottlenecks in DSP and packet processing. There is greatly enhanced DSP processing, high-speed memory cascading, and hardened IP for I/O intensive functions.
Next generation power management features also enable a leap in performance. The process node is up to 35 percent static at 20nm. There are more buffers for granular or coarse clock gating. Block RAM is dynamic power gating, hardened cascading. For transceivers, there are architectural optimizations. There is efficient packing and utilization of the logic fabric. For DSP, there are wider multipliers and fewer blocks per function. As for memory, there is DDR4, which operates at 1.2v vs.1.5v, voltage scaling.
The Xilinx KINTEX UltraSCALE will power 4×4 mixed-mode radios, 100G traffic manager NICs, super high-vision processing, 256-channel ultrasound and 48-channel T/R radar processing. The Xilinx VIRTEX UltraSCALE will power 400G OTN switching, 400G transponder, 400G MAC-to-Interlaken bridge, 2x100G muxponder and ASIC prototyping.
Xilinx worked with TSMC to infuse high-end FPGA requirements into the TSMC 20SoC development process, just as it had done in the development of 28HPL. The Xilinx Vivado Design Suite early access supporting UltraScale architecture-based FPGAs is now available. Initial UltraScale devices will be available in Q4-2013.
Its a pleasure to talk to Dr. Walden (Wally) C. Rhines, chairman and CEO, Mentor Graphics Corp. On his way to DAC 2013, where he will be giving a ten-minute “Visionary Talk”, he found time to speak with me. First, I asked him given that the global semiconductor industry is entering the sub-20nm era, will it continue to be ‘business as usual’ or ‘it’s going to be different this time’?
Dr. Rhines said: “Every generation has some differences, even though it usually seems like we’ve seen all this before. The primary change that comes with “sub-20nm” is the change in transistor structure to FinFET. This will give designers a boost toward achieving lower power. However, compared to 28nm, there will be a wafer cost penalty to pay for the additional process complexity that also includes two additional levels of resolution enhancement.”
Impact of new transistor structures
How will the new transistor structures impact on design and manufacturing?
According to him, the relatively easy impact on design is related to the simulation of a new device structure; models have already been developed and characterized but will be continuously updated until the processes are stable. More complex are the requirements for place and route and verification; support for “fin grids” and new routing and placement rules has already been implemented by the leading place and route suppliers.
He added: “Most complex is test; FinFET will require transistor-level (or “cell-aware”) design for test to detect failures, rather than just the traditional gate-level stuck-at fault models. Initial results suggest that failure to move to cell-aware ATPG will result in 500 to 1000 DPM parts being shipped to customers.
“Fortunately, “cell-aware” ATPG design tools have been available for about a year and are easily implemented with no additional EDA cost. Finally, there will be manufacturing challenges but, like all manufacturing challenges, they will be attacked, analyzed and resolved as we ramp up more volume.”
Introducing 450mm wafer handling and new lithography
Is it possible to introduce 450mm wafer handling and new lithography successfully at this point in time?
“Yes, of course,” Dr. Rhines said. “However, there are a limited number of companies that have the volume of demand to justify the investment. The wafer diameter transition decision is always a difficult one for the semiconductor manufacturing equipment companies because it is so costly and it requires a minimum volume of machines for a payback. In this case, it will happen. The base of semiconductor manufacturing equipment companies is becoming very concentrated and most of the large ones need the 450mm capability.”
What will be the impact of transistor variability and other physics issues?
As per Dr. Rhines, the impact should be significant. FinFET, for example requires controlling physical characteristics of multiple fins within a narrow range of variability. As geometries shrink, small variations become big percentages. New design challenges are always interesting for engineers but the problems will be overcome relatively quickly.
Some time ago, Cadence Design Systems Inc. had announced the EDA360 vision! As per Jaswinder Ahuja, corporate VP and MD of Cadence Design Systems India, the Cadence vision of EDA360 is said to be well and alive. The organization has been aligned around the EDA360 vision.
The EDA360 is a five-year vision for defining the trends in the EDA industry, based on what Cadence is observing in the industry and the direction in which, it feels, the industry will go.
At Cadence, the Silicon Realization Group is headed by Dr. Chi-ping Hsu. The SoC Realization Group is headed by Martin Lund, and Nimish Modi is looking after the System Realization Group. Cadence’s focus has been on in-house development and innovation. Tempus has been a major announcement from the Silicon Realization Group.
What’s going on with EDA360?
There has been a renewed thrust in the SoC Realization Group at Cadence. Already, there have been three acquisitions this year — Cosmic Circuits, Tensilica and Evatronix. Cadence is buying the IP part of the business from Evatronix. This acquisition is ongoing and will be announced in June 2013.
On the relationship between the electronics and the EDA industries, Ahuja said the electronics industry is going through a transition, and that the EDA industry needs to change. The importance of system-level design has increased. Companies are currently focusing on optimizing the end user experience.
Cadence Design Systems Inc. has announced the Tempus timing signoff solution. It facilitates ground-breaking signoff timing analysis and closure. The new technology accelerates timing analysis and closure by weeks. It is said to be up to 10X faster than competing solutions. Tempus has also been endorsed by Texas Instruments (TI).
Complexity is growing exponentially and signoff is the bottleneck. There is an increasing design complexity. Low power is important across markets — from smartphones to datacenters. Time to market remains critical as well. Feature-rich devices are growing the design size.
Timing closure schedule and complexity have been increasing. In fact, up until now, timing closure solutions are said to have not kept pace with design complexity. The number of timing views are increasing with each new process node. The increased margins make timing closure very difficult. Exponential growth in design size and complexity are stretching the analysis capacity. Time in signoff closure has been increasing up to 40 percent of the design flow at 20nm.
The Tempus timing signoff solution is big on performance, accuracy and closure. For performance, it facilitates massively parallelized computation, is scalable to 100s of CPUs and there are optimized data structures. It allows up to 10X faster path-based analysis (PBA) and advanced process modeling for accuracy. Finally, for closure, it provides up to 10X reduction in closure time, is placement and routing aware and offers unlimited MMMC capacity.
Tempus offers an unprecedented performance, and handles 100s of millions of cells flat! It has an innovative hierarchical/incremental analysis. For design closure, the multi-mode, multi-corner (MMMC) is distributed or concurrent. There is physically aware optimization, such as graph- or path-based. The PBA is a detailed view of timing based on slew propagation.
With Tempus, Cadence is solving the design complexity challenge by eliminating the signoff bottleneck and enabling customers to meet power, performance and time-to-market goals.
We are now entering the sub-20nm era. So, will it be business as usual or is it going to be different this time? With DAC 2013 around the corner, I met up with John Chilton, senior VP, Marketing and Strategic Development for Synopsys to find out more regarding the impact of new transistor structures on design and manufacturing, 450mm wafers and the impact of transistor variability.
Impact of new transistor structures on design and manufacturing
First, let us understand what will be the impact of new transistor structures on design and manufacturing.
Chilton said: “Most of the impact is really on the manufacturing end since they are effectively 3D transistors. Traditional lithography methods would not work for manufacturing the tall and thin fins where self-aligned double patterning steps are now required.
“Our broad, production-proven products have all been updated to handle the complexity of FinFETs from both the manufacturing and the designer’s end.
“From the design implementation perspective, the foundries’ and Synopsys’ goal is to provide a transparent adoption process where the methodology (from Metal 1 and above) remains essentially the same as that of previous nodes where products have been updated to handle the process complexity.”
Given the scenario, will it be possible to introduce 450mm wafer handling and new lithography successfully?
According to Chilton: “This is a question best asked of the semiconductor manufacturers and equipment vendors. Our opinion is ‘very likely’.” The semiconductor manufacturers, equipment vendors, and the EDA tool providers have a long history of introducing new technology successfully when the economics of deploying the technology is favorable.
The 300nm wafer deployment was quite complex, but was completed, for example. The introduction of double patterning at 20nm is another recent example in which manufacturers, equipment vendors and EDA companies work together to deploy a new technology.
Impact of transistor variability and other physics issues
Finally, what will be the impact of transistor variability and other physics issues?
Chilton said that as transistor scaling progresses into FinFET technologies and beyond, the variability of device behavior becomes more prominent. There are several sources of device variability.
Random doping fluctuations (RDF) are a result of the statistical nature of the position and the discreteness of the electrical charge of the dopant atoms. Whereas in past technologies the effect of the dopant atoms could be treated as a continuum of charge, FinFETs are so small that the charge distribution of the dopant atoms becomes ‘lumpy’ and variable from one transistor to the next.
With the introduction of metal gates in the advanced CMOS processes, random work function fluctuations arising from the formation of finite-sized metal grains with different lattice orientations have also become important. In this effect, each metal grain in the gate, whose crystalline orientation is random, interacts with the underlying gate dielectric and silicon in a different way, with the consequence that the channel electrons no longer see a uniform gate potential.
The other key sources of variability are due to the random location of traps and the etching and lithography processes which produce slightly different dimensions in critical shapes such as fin width and gate length.
“The impact of these variability sources is evident in the output characteristics of FinFETs and circuits, and the systematic analysis of these effects has become a priority for technology development and IP design teams alike,” he added.
Agnisys Inc. was established in 2007 in Massachusetts, USA, with a mission to deliver innovative automation to the semiconductor industry. The company offers affordable VLSI design and verification tools for SoCs, FPGAs and IPs that makes the design verification process extremely efficient.
Agnisys’ IDesignSpec is an award winning engineering tool that allows an IP, chip or system designer to create the register map specification once and automatically generate all possible views from it. Various outputs are possible, such as UVM, OVM, RALF, SystemRDL, IP-XACT etc. User defined outputs can be created using Tcl or XSLT scripts. IDesignSpec’s patented technology improves engineer’s productivity and design quality.
The IDesignSpec automates the creation of registers and sequences guaranteeing higher quality and consistent results across hardware and software teams. As your ASIC or FPGA design specification changes, IDesignSpec automatically adjusts your design and verification code, keeping the critical integration milestones of your design engineering projects synchronized.
Register verification and sequences consume up to 40 percent of project time or more when errors are the source of re-spins of SoC silicon or an increase in the number of FPGA builds. IDesignSpec family of products is available in various flavors such as IDSWord, IDSExcel, IDSOO and IDSBatch.
IDesignSpec more than a tool for creating register models!
Anupam Bakshi, founder, CEO and chairman, Agnisys, said: “IDesignSpec is more than a tool for creating register models. It is now a complete Executable Design Specification tool. The underlying theme is always to capture the specification in an executable form and generate as much code in the output as possible.”
The latest additions in the IDesignSpec are Constraints, Coverage, Interrupts, Sequences, Assertions, Multiple Bus Domains, Special Registers and Parameterization of outputs.
“IDesignSpec offers a simple and intuitive way to specify constraints. These constraints, specified by the user, are used to capture the design intent. This design intent is transformed into code for design, verification and software. Functional Coverage models can be automatically generated from the spec so that once again the intent is captured and converted into appropriate coverage models,” added Bakshi.
Using an add-on function of capturing Sequences, the user is now able to capture various programming sequences in the spec, which are translated into C++ and UVM sequences, respectively. Further, the interrupt registers can now be identified by the user and appropriate RTL can be generated from the spec. Both edge sensitive and level interrupts can be handled and interrupts from various blocks can be stacked.
Assertions can be automatically generated from the high level constraint specification. These assertions can be created with the RTL or in the external files such that they can be optionally bound to the RTL. Unit level assertions are good for SoC level verification and debug, and help the user in identifying issues deep down in the simulation hierarchy.
The user can now identify one or more bus domains associated with Registers and Blocks, and generate appropriate code from it. Special Registers such as shadow registers and register aliasing is also automatically generated.
Finally all of the outputs such as RTL, UVM, etc., can be parameterized now, so that a single master specification can be used to create outputs that can be parameterized at the elaboration time.
How is IDesignSpec working as chip-level assertion-based verification?
Bakshi said: “It really isn’t an assertion tool! The only assertion that we automatically generate is from the constraints that the user specifies. The user does not need to specify the assertions. We transform the constraints into assertions.”