<title>Design and manufacturability tradeoffs in unidirectional and bidirectional standard cell layouts in 14 nm node</title>

Abstract

The 14 nm node is seeing the dominant use of three-dimensional FinFET architectures, local interconnects, multiple patterning processes and restricted design rules. With the adoption of these new process technologies and design styles, it becomes necessary to rethink the standard cell library design methodologies that proved successful in the past. In this paper, we compare the design efficiency and manufacturability of standard cell libraries that use either unidirectional or bidirectional Metal 1. In contrast to previous nodes, a 14 nm 9-track unidirectional standard cell layout results in up to 20% lower energy-delay-area product as compared to the 9-track bidirectional standard cell layout. Manufacturability assessment shows that the unidirectional standard cell layouts save one exposure on Metal 1, reduces process variability by 10% and layout construct count by 2-3X. As a result, the unidirectional standard cell layout could serve as a key enabler for affordable scaling.

Metamaterial superconductors

“…An example of high  metamaterial geometry, which is amenable to lithographic fabrication using currently available 14 nm node technology [27] is presented in Fig.4(a). It is based on the approach to high  THz metamaterials, which was experimentally developed in [21].…”

Review of computational lithography modeling: focusing on extending optical lithography and design-technology co-optimization

“…A simpler OPC [47] and a reduced number of hotspots are possible as shown in Figure 26 . Much fewer constructs are needed for the designers to construct standard cell designs for unidirectional designs [48,49] . This actually might be a more effective form of DTCO that can drive to a true global optimum in terms of design and manufacturing cost for the scaling ≠ A B Figure 22 Example of (A) conventional illumination and (B) SMO pixelated illumination.…”

“…Figure 27 shows some preliminary study comparing bidirectional M1 designs and unidirectional designs with the constraint that the total cell areas are kept more or less the same [48] .…”

“…Illustration of the benefit of using computational lithography techniques when comparing unidirectional designs to bidirectional designs [48] .…”

Enabling complex nanoscale pattern customization using directed self-assembly

“…For instance, unidirectional integrated circuit layouts based on a fixed line period 22 may be amenable to the use of DSA-fabricated grating patterns, but such designs still require patterning semi-periodic, isolated and discontinuous features in potentially complicated arrangements on the same layer. This necessitates customization of DSA patterns at very high resolution.…”