With the help of Fraunhofer IIS/EAS, the international semiconductor manufacturer LFoundry is preparing its 150 nm technology to support applications that are especially safety critical. Thanks to their joint work, in the future it will be possible for the first time to make a more precise forecast about the overall reliability of an integrated circuit in this technology before it is used in practice. As a result, the applications of European microelectronics will be significantly expanded in areas such as the automotive sector.
Reliable and durable electronics are essential for an increasing number of applications. This is all the more true for safety-critical features such as in automobiles or industrial automation. During their operation, electronic systems are often exposed to heavy loads that intensify aging phenomena in transistors and can therefore negatively affect the function of components. If semiconductor manufacturers want to offer durable components in these application fields, they therefore need to provide proof that individual transistors can perform their task perfectly under defined operating conditions even after a long time. Furthermore, being able to analyze already in the design phase the long-term behavior of circuits consisting of these transistors is of critical importance to electronics manufacturers.
During the joint work of Fraunhofer IIS/EAS with LFoundry, the primary focus was on meaningful models that are integrated into so-called “process design kits” (PDK) to allow aging simulations. Using PDKs, the semiconductor manufacturer’s customers are able to bring their own developments to the market quickly on the basis of LFoundry technologies. What is new is that the LF15A PDK for components in the 150nm technology, which is dedicated to a wide field of mixed signal applications including low power, high voltage and RF, now includes information about the reliability of transistors under practical loads. This can be used to verify the long-term behavior of entire circuits. In this structure size, only simplified models for individual transistors are currently customary in the industry, which do not allow conclusions to be drawn about overall circuit reliability in actual use.
"In order to best support the design flow with regard to the high quality requirements in the field of automotive product development, models for ageing simulation were integrated into our LF15A platform in the course of this project. This gives our customers the opportunity to better predict the product life cycle.” points out PDK Director Andreas Haertl from LFoundry.
In the project, the researchers at Fraunhofer IIS/EAS primarily analyzed the effects of different wear-out mechanisms on LF15A components. “We primarily measured the consequences of the widespread effects hot-carrier injection (HCI) and negative-bias temperature instability (NBTI) on CMOS components,” Fraunhofer head of the department for design methodology Roland Jancke explained. “With this knowledge, we were then able to adjust the parameters for the aging models in use, so that now for the first time these can demonstrate the reliable function of complete circuits even after a long load period.”
It is expected that LFoundry will make the expanded PDK with the LF15A aging information available to its customers in November. Furthermore, together with Fraunhofer, additional optimizations of the proof of reliability are planned. For example, in the future even more precise simulation results will be obtained from advanced aging models so that the electronics can also be used more specifically in additional application areas.