After Five Years, 28nm Future Remains Bright!

Five years ago TSMC started 28nm mass production and it went on to become one of the most versatile and successful process technologies in history. The first wave was triggered by an unprecedented demand for application processors from smartphone and tablet vendors. Today it’s widely assumed that 28nm demand will continue growing with the introduction of mid- and low-end smartphones, burgeoning Internet of Things applications, and other second-wave opportunities such as automotive.

Not resting on its laurels, TSMC recently announced several significant process improvements to offer its customers and they are increasing capacity to accommodate strong ongoing demand for 28nm solutions.

As we all know, the performance requirement is different for entry level, mainstream, and high-end products. However, today’s performance spec for high-end products will become tomorrow’s mid-range spec so TSMC needs to continue to improve its portfolio by offering a range of options. Accordingly, the company introduced 28HPC to address 64-bit CPU core conversion to roughly 2GHz performance because 64-bit CPU performance is limited by the power budget.

This year they added 28HPC+ that offers 15% faster speed compared to 28HPC. 28HPC+ can allocate more power budget to push CPU/GPC performance significantly over 2 GHz while staying within the same power budget. 28HPC+ also achieves an additional 30% performance at sign-off condition which allows designers to replace the 28HPC LVT transistors with 28HPC+ SVT transistors. As a result, it can reduce leakage by 80% on high-speed sensitive circuits. Equally impressive, TSMC has worked with its design ecosystem partners to support an easy IP migration from 28HPC to 28HPC+. As you can see from the blue box, all that’s needed is to re-characterize the standard cell library and SRAM complier. There is no change of I/Os. And you simply need to re-simulate and fine-tune analog devices in order to enjoy the greater values of 28HPC+.
The next innovation is 28ULP (ultra-low power). It is based on 28HPC with 30% power reduction and optimized for IoT and wearables. It provides a simple power grid, multiple gate length advantages, smaller die size, a broader portfolio of multi-source IPs, and a shorter cycle time that translates to a faster time-to-market. According to TSMC, when compared to FD-SOI, 28ULP is much more competitive in both performance and low-power. 28ULP offers multiple Vt options with multiple gate bias options, versus FD-SOI’s 2 Vt’s with body bias and gate bias at nominal Vdd.

It should be noted that the extensive body bias implementation in 28FD-SOI not only significantly increases design complexity but also die area.

RF is another trend addressed by 28HPC-RF and the proliferation of RF into LTE RF Transceiver and WiFi/BT combo applications. Advanced RF CMOS technology is needed for longer range and higher data rate, especially in mobile communication which is 4G/LTE now. And further demonstrating 28nm adaptability, TSMC is the first foundry to certify these technologies for automotive production. Multiple customers have completed automotive qualifications compliant with AEC-Q100 for grade-one specs.

Given its outstanding track record over the past five years, there is little doubt that the future for TSMC 28nm technology will continue to be very bright and highly productive, absolutely.