Submicrometer-scale patterning of ceramic thin films

The patterning of ceramic thin films is of great interest for use in MEMS and other applications. However, the complex chemistries of certain materials make the use of traditional photolithography techniques prohibitive. In this paper, a number of low-cost, high throughput techniques for the patterning of ceramic thin films derived from chemical solution precursors, such as sol-gels and ceramic slurries, are presented. A particular emphasis is placed on methods that are derived from soft lithographic methods using elastomer molds. Two categories of techniques are discussed: first, the focus is on methods that rely on the principles of confinement within the physical features of the mold to define the pattern on the substrate surface. Then, subtractive patterning techniques that rely on transferring a pattern to a spin-cast, large-area continuous thin film are described. While most techniques have been demonstrated with fidelities on the order of 100 nm, their inability to precisely register and align the patterns as part of a hierarchical fabrication scheme have thus far hindered their commercial implementation.