At the LIPSION accelerator facility the technique of proton beam writing has been modified by introducing aspects of ion beam tomography, so far solely an analysis method.

Key element of the new procedure is the targeted irradiation of resist material from multiple angles, thus obtaining a much broader class of fabricable structures.

Patterns corresponding to the silhouettes of the desired structures were written from two or three angles into upright 90 µm thin PMMA columns using a focused beam of 2.25 MeV protons. During chemical development irradiated portions were dissolved, leaving behind the finished 3D sculpture.

To demonstrate the variety of the method several microsculptures have been created, such as a model of the Eiffel tower, a human and an equine figure all smaller than 100 µm. Using irradiation from three angles a 40 µm wide screw with right-handed thread could be crafted which might find application in micromachining. Also, cage structures with a pore size of ca. 20 µm were written with the intention to use them as scaffolds for the growth of biological cells.