The use of proton microbeams for the production of microcomponents

The recently developed process of high-energy ion beam micromachining (proton micromachining) is discussed. Proton micromachining is a novel process for the production of high aspect-ratio 3D microstructures. The sub-micron lateral resolution and the well-defined range of an MeV proton microbeam are utilized to make lithographic structures in suitable polymers (e.g., SU-8, PMMA). Sub-micron structures with a depth of tens of microns and aspect-ratios approaching 100 have been achieved. The use of different energies for multiple exposures allows the production of intricate 3D multi-layer structures in a single polymer layer, and because no mask is needed the process offers a wide range of possible geometries for the production of non-prismatic or even rounded features. The throughput of the technique does not compare favourably with conventional (masked) processes for high volume batch production of microcomponents. On the other hand, significant applications of high-energy ion beam micromachining may be developed, e.g. for the rapid production of prototypes, the research into the characteristics of microstructures, and the manufacture of molds, stamps and X-ray masks. (C) 2000 Elsevier Science B.V. All rights reserved.