Seminars

The Light at the End of the CMOS Tunnel

Thursday, September 22, 2011

Abstract

In spite of numerous predictions to the contrary, Silicon technology is marching along past the 22nm node and on to ever finer dimensions. Innovations at the technology, device, circuit and system levels continue to enable us to scale in spite of what sometime appear to be insurmountable problems in power, lack of performance, manufacturability and so on. To a large degree, these innovations are necessary because no substitute technology has been found as yet and, in fact, it does not appear likely that any such technology will become practical this decade. This leaves us with the need to anticipate and predict the near and medium term futures of CMOS for the next handful of technology nodes. This talk will focus on doing just that by reviewing three important problem areas: lithography (our ability to create wafer images of the appropriate scale), power (which is now the key challenge for integrated circuits), and resilience (the fact that in the future we cannot guarantee that all fabricated devices on a chip will be operational).

Lithography and Power are relatively well known as challenges to continued scaling. Resilience is somewhat less popular, and demands that circuits continue to operate in spite of challenges like noise, difficult environmental conditions, aging and manufacturing imperfections. These factors conspire to cause transient or permanent errors that are indistinguishable from traditional "hard" faults typically caused by defects during fabrication. Without significant innovation at the circuit and system levels, the probability of these events can rise quite dramatically. In the area of SRAM, such phenomena have existed for the last three or four technology nodes, but significant investments in this area have indeed allowed continued system level scaling with ever larger on-chip memories. As these same phenomena start attacking integrated circuits more pervasively, there is an urgent need for research and development in this area to avert the problems certain to arise with increased defect rates.