Topographic templates can direct the self-assembly of block copolymers to achieve nanoscale patterns with high order. Previously, we have demonstrated well-aligned periodic lines, bends, and meshes using a sparse array of lithographically defined posts [1,2]. However, it is generally challenging to fabricate complex and non-periodic patterns using a sparse post array because the key information contained in the final pattern must be encoded in the sparse template. In this work, we present two cell-based design methods for fabricating complex patterns using directed self-assembly of polystyrene-b-polydimethylsiloxane (PS-b-PDMS) block copolymer thin films. For the first approach, we developed a set of template tiles consisting of square post lattices with a restricted range of geometric features. For all possible tile arrangements, we examined the resulting block copolymer patterns. We were able to predict a relatively simple template that will result in a desired complex pattern by combining tiles in different ways. For the second approach, we designed a binary-state system with ladder-shaped block copolymer structures using a square confinement. We developed design-rules for controlling alignment direction of the ladder-shaped structures by introducing openings around the square cells. These methods could provide a new template design method for a complex non-trivial block copolymer patterns.

Superconductive technology is one of the most promising approaches to quantum computing because it offers devices with little dissipation, ultrasensitive magnetometers, and electrometers for state readout, large-scale-integration, and a family of classical electronics that could be used for quantum bit (qubit) control. The challenges this technology faces, however, are substantial: for example, control of the qubit to a part in /spl sim/10/sup 4/ must be accomplished with analog control pulses. But even after this is done, the accuracy is limited by the unavoidable decay of quantum information in the system. Recent experiments suggest the time over which this decay occurs is <1 /spl mu/s, though it is expected to lengthen as experimental methods improve. A 1-/spl mu/s decay time would mandate a very difficult to achieve maximum time of /spl sim/100 ps per analog operation. Thus, quantum computing is, simultaneously a promising technology for solving certain very hard problems in computer science and a daunting challenge for those working to develop that technology.