An important aspect of our work is the ability to place patterns exactly where needed with respect to existing structures. In complex fabrication projects, with many layers of processing, this layer-to-layer alignment is critical. We are typically able to achieve alignments to better than 20nm over many centimeters of sample, and often to better than 10nm. Figure 4 shows an example of aligned structures, with two sets of lines crossed to form a 3x3 cross-point phase-change memory array.

Figure 4. Cross-point memory array, showing two layers aligned to each other. The line period here is 100nm.