Multi billion dollar semiconductor companies like intel and IBM try to increase the speed and decrease the power and the size of their chips. For this purpose, they always try to use smaller and smaller transistors where smaller transistors mean more functional chips with higher speeds. For instance, Intel processors had started with 10 um (micro meter) transistors in 1971 for manufacturing Intel 4004. Intel 4004 had only 2300 transistors and its speed was 108 KHz. By 2007, only after about 35 years, the transistor sizes had become 45 nm (nanometer), which was used to manufacture Intel Core2 Extreme processors. The number of transistors in these processors were more than 820,000,000 and the speed of the processors was more than 3 GHz.
However, decreasing the transistor sizes to produce digital ICs (Integrated Circuits or chips) with smaller area and higher speeds has led up to many problems. Now the chip manufacturing process is prone to errors and variations. The statistical variations of the transistor and circuit parameters result in many chips thrown away after manufacturing as they can not satisfy the timing requirements. As a result, it became an obligation to consider the statistical variations of digital circuits in stages before manufacturing and perform statistical timing analysis to estimate timing yield before manufacturing.
Today, many companies like Intel, IBM, Cadence, Synopsis, Mentor; many Computer Aided Design (CAD) research groups in academic institutions like Berkeley, MIT, Carnegie Mellon try to develop a statistical timing analysis tool that can estimate timing yield accurately and efficiently.
We also work on this topic and develop accurate and efficient statistical timing analysis tools to estimate timing yield of digital circuits. MS candidates eager to work on this topic are welcome. For further information please check the following papers:
The History of Intel Processor Technology
Why are Timing Estimates so Uncertain?
Statistical Timing Analysis Survey
Fast Monte Carlo Estimation of Timing Yield
