Direct bonding and beyond

We present a number of recent evaluations of direct bonding, a glueless bonding technology, performed under ambient conditions. If combined with bond-strengthening, this geometry-conserving technology is well suited for an application in far ultraviolet immersion lithography. Our term beyond direct bonding refers to taking at least one additional technological step beyond direct bonding, involving chemical interface engineering, advanced silicon-on-insulator (SOI) technology, whereby the unwanted influence of dilatation mismatch is obviated. The combination of successive direct bonding, nanopillar lattice structures and silicon-technological engineering makes it possible for us to arrange quantum dots, wires, and planes in a transversal cascade. We also address the interrelationship between direct bonding and elasticity, as well as plasticity; the latter is in relation to direct bonded glass wafers that are thermally treated to create the geometric shape, e.g., required for specific lab-on-a-chip components with a three-dimensional overall configuration.