Application-independent defect tolerance of reconfigurable nanoarchitectures

Self-assembled nanofabrication processes yield regular and reconfigurable devices. However, defect densities in this emerging nanotechnology are higher than those in conventional lithography-based VLSI. In this article, we present an application-independent defect tolerant design flow to minimize customized postfabrication design efforts to be performed per chip. In this flow, higher level design steps are not needed to be aware of the existence and the location of defects in the chip. Only a final mapping step is required to be defect aware. Application independence of this flow minimizes the number of per-chip design steps, making it appropriate for high volume production. We also present two mapping algorithms, recursive and greedy, which make the connection between defect-unaware design steps and the final defect-aware mapping step. Experiments show that the results obtained by the greedy algorithm are very close to the exact solutions. Using these algorithms, we analyze the manufacturing yield of molecular crossbars under different defect distribution models. We report on the size of the minimum crossbar to be fabricated such that a defect-free crossbar of the desirable size can be found with a guaranteed manufacturing yield.