Process monitoring IP can found within Moortec’s embedded PVT Subsystem which has been designed to optimise performance in today’s cutting-edge technologies, solving the problems that come about through scaling of devices. Applications include Datacentre & Enterprise, Automotive, AI, Mobile, IoT, Consumer and Telecommunications.
The Moortec Process Monitor provides the means for advanced node Integrated Circuit (IC) developers to detect the process variation of core digital MOS devices. The Process Monitor can also be used to enable continuous Dynamic Frequency and Voltage Scaling (DVFS) optimisation systems, monitor manufacturing variability across chip, gate delay measurements, critical path analysis, critical voltage analysis and also monitor silicon ‘ageing’.
Process induced variations in circuit delays have begun to significantly adversely affect chip performance and power consumption. A statistical analysis of each device would show a process variability, or spread, that when compared to historical CMOS technologies is wider (worse) for advanced technology nodes. To address this, manufacturers have to design their Systems-on-Chip (SoC) to over-compensate for unwanted variability arising from manufacturing processes.
Process variation is a complex subject which covers a range of effects, but broadly we can consider that the effects are caused by imperfections in the manufacturing process. Examples are implant variations, mask misalignments, and optical variations. These all add up to give statistical variation on the ideal or “typical” transistor.
However, the mechanisms and causes of the variation are not particularly our concern. What we are interested in is being able to measure in a meaningful way where a particular piece of silicon is within the defined process space for the technology being utilised.
Because ultimately, the measurement of process is being used to assist with optimising performance, we relate process to speed and in advanced nodes this comes down to MOS device speed, and the parasitics of the interconnect.
Process variability has always been an issue and the design process has taken account of the variability, often by designing for worst case. Whilst this is still possible doing so is eroding a larger proportion of the gains made by migrating to an advanced node and when this is coupled with additional sensitivities to supply voltage (an effect of the dropping of core supplies) we are at a point now where process variation and specifically, designing for worst case is too high.
There are a range of applications for making use of process data. The first is using the data performance optimisation. The simplest implementation of this is speed binning devices. A more detailed performance optimisation is to use this process data to optimise that die with a DVFS optimisation process. This can either be once, to take process into account, or could be used over time to account for temperature and even ageing. It is possible, for example, to reduce power consumption to achieve a desired speed of operation. It is also possible to take process variation across a die into account, which is being done in large SoCs today.
Another application is in detecting ageing of a chip. This can be either as part of performance optimisation, as described above, or to predict device failure.
Ultimately process, voltage, and temperature are all interrelated because they all determine how fast a chip will work, or how much power it will burn doing a given task. By having accurate measurements of all three allows SoC designers to take advantage of the performance which would otherwise be left as margin.
Established in 2005 Moortec provides compelling embedded sub-system IP solutions for Process, Voltage & Temperature (PVT) monitoring, targeting advanced node CMOS technologies from 40nm down to 7nm. Moortec’s in-chip sensing solutions support the semiconductor design community’s demands for increased device reliability and enhanced performance optimization, enabling schemes such as DVFS, AVS and power management control systems. Moortec also provides excellent support for IP application, integration and device test during production.