Solving the problem of growing ASIC respins

Semiengineering.com recently reported on an industry survey showing an increase in respins due to analog circuitry failing or falling out of operable range.

The reasons behind this trend are complex, but the article suggests it comes down to analog tuning – the process of tweaking a design to maximise performance while staying within the operational parameters of the overall circuit. The article also explains that the chief scientist at Mentor, a Siemens Business, analysed the results to determine the scale and scope of this trend – whether it was affecting newer designs on the latest technology nodes, or if it was a universal problem.

Figure 1: Flaws contributing to ASIC re-spins. Source: Wilson Research and Mentor, a Siemens Business

It would be easy to assume that the problem was relating to newer nodes and newer processes, but on review, the issues are affecting technology nodes from sub-7nm to 150nm and higher.

Figure 2: Tuning analog circuit flaws by design size. Source: Wilson Research and Mentor, a Siemens Business

So what’s causing the increase in failures?

Put simply, the complexity of new devices. The number of complex devices is growing, and is set to continue with the expansion of the IoT. Automotive components are also massively on the rise, both in number and complexity, thanks to the developments towards self-driving cars. Companies are trying to fit all circuitry on the same substrate or on a single technology node and schematic simulation isn’t able to accurately assess function and full parameters.

Fig 3: Defect rates for automotive ICs and causes of failures. Source: Mentor, a Siemens Business

There will always be issues arising when working with new nodes and there is a learning curve for design teams to fully come to terms with the limitations, issues and particular traits displayed by these new nodes. Implementing this knowledge into toolsets is only achievable once they are fully understood. But if that learning curve therefore involves respins and ‘back to the drawing board’ moments at increasing frequency, then time to market will be affected for new devices. And increasing time to market for a new chip in a competitive industry can be the difference between market success and failure. Second place really is the first loser.

As IP reuse specialists, this is not news to us. We have worked with many clients evolving analog IP from one technology to another or even from one foundry to another. Most engagements are accompanied with the need to improve power consumption, speed, performance or the physical size of the silicon chip, and when these needs are implemented, they have knock on effects to other characteristics, resulting in the silicon not performing to specification.

We know this; it’s what we do. It’s why we developed our technology analyzer to be able to identify differences between base and target technologies and highlight where a circuit will fail. Our Trifecta, including the AMALIA platform, helps to identify the root cause of an issue and allows our design engineers to nudge a design back into specification before migration; mitigating the need for respins for out-of-tolerance circuits.

As experts in reusing analog IP on different process nodes or technologies, we’ve spent years developing processes to ensure IP works as expected and as needed in target technologies. We do this by deploying our Trifecta – advanced development methodologies, the targeted automation of our AMALIA platform and our design expertise. Using this Trifecta approach means we can verify IPs and their behaviour or performance before migration. Part of the AMALIA platform uses our proprietary technology analyzer to rapidly identify parameters in both base and target technologies to identify issues, allowing our expert designers to tweak characteristics and knock the design into specification.

This methodology, used by us across multiple technology nodes and foundries, has the potential to play a significant role in the fast and efficient migrating of analog IP for the ever-increasing number of IoT, mobile and handheld devices. Analog components sit alongside digital and ensuring everything functions as it should is key in getting new products to market ahead of the competition.

Hands-free driving – and the technology behind it

Hands-free driving could be legal on UK roads by spring next year, the UK government has said. A consultation on the technology involved is under way. Specifically the UK’s Department for Transport (DfT) has issued a call for evidence into automated lane keeping systems (ALKS).

The technology to do this is still very much developing, although we can certainly expect that it will make significant demands on the semiconductor industry that Thalia serves. But first some background.

This consultation looks at level three (of five) on the way to the ultimate aim of completely automated driving. In stage two the vehicle can control both steering and acceleration / deceleration. The automation isn’t classed as self-driving because a human is still required to sit in the driver’s seat and be prepared to take control of the car at any time.

Level 3 vehicles, however, have what are called environmental detection capabilities and can make informed decisions for themselves, such as accelerating past a slow-moving vehicle. The driver must remain alert and ready to take control if the system is unable to execute the task but, in theory, the driver could do other things such as check email or even watch a movie – until the car prompts him or her to take over again.

But don’t get too excited just yet. The UK government’s call for evidence, at some 46 pages, makes some pretty stern safety demands of what it calls ‘a traffic jam chauffeur technology designed to control the lateral and longitudinal movement of the vehicle for an extended period without further driver command’. These demands include a driver availability recognition system, reasonable thresholds designed to prevent unintentional inputs into the override capabilities, a data storage system for automated driving and numerous compliance requirements involving monitoring and control criteria – to name but a few.

But that isn’t all. The ALKS regulation approved in June 2020 by the United Nations Economic Commission is for a system (in its current form) capable of operating at speeds of up to just 37mph. It is therefore designed for situations of heavy, slow-moving traffic on a motorway. Why motorways? Because they go one way and are more controlled and simpler environments than most others. A slow-moving motorway is a good place to try out stage three ALKS.

Elsewhere in Europe, Germany has drafted legislation for level 4 autonomous vehicles. As yet, the legislation remains unpublished, but Germany, as the country of origin for most OEMs relating to the technology behind assisted and self-driving vehicles, could expect to see the reality of self-driving vehicles sooner rather than later. If this is the case, German legislation will likely guide all other nations legislative developments.

Even with the restrictions at levels 3 and 4 of automation, the market seems to be a promising one. According to a report released earlier this year by Acumen Research and Consulting, the global automotive lane keep assist system market is expected to reach a market value of around US$7 billion by 2026 and is anticipated to grow at a CAGR of around 16% in terms of revenue during the report’s forecast period 2019 to 2026.

It will no doubt mean a lot of work supplying a whole new market with tech – and a whole new semiconductor market with relevant IPs. And, of course, this market has a lot of development to do; new requirements, new sensors, new software and new hardware will supersede each other. Within a lot less than ten years, we may see not only level four (vehicles operating in self-driving mode within a limited area) but early level 5 cars: able to go anywhere and do anything that an experienced human driver can do.

As for public acceptance of ALKS, we can certainly assume that even hiccoughs or bad publicity will only slow rather than stop the rollout of this form of automated driving, and that when the first completely autonomous cars arrive – sometime after 2026 in all likelihood – a $7 billion market will just be the start.