Self-assembly solder process to form three-dimensional structures on silicon.

The self-assembly of microscale polyhedra driven by surface-tension constraints has been previously described in the literature. Lithographic techniques were used to fabricate two-dimensional structures that, when freed from the underlying substrate, folded into polyhedral shapes. In this article, a modified technique is described in which one face of each polyhedron remains attached to the silicon substrate. The advantage of this new approach is that precise arrays of polyhedra can be formed. Five different polyhedral shapes were fabricated and their corresponding yields are given. The yield values show that the success of the autofolding process depends on the shape of the three-dimensional structures. Truncated shapes appear to be the most readily assembled. [ABSTRACT FROM AUTHOR]