Black silicon - new functionalities in microsystems

Black silicon and its application as a new assembly method for silicon wafers at room temperature is presented. Needle-like structures on the surface after deep reactive ion etching with a length of 15-25 mu m and 300-500 nm in diameter interlock with each other to form a bonding interface. After compression of two wafers at room temperature they generate retention forces up to 380 N cm(-2) (3.8 MPa). If low contact forces are applied with partially interlocking of the needles, it is possible to generate a reversible Velcro (R)-like assembly. This new bonding process can be used for applications in the area of microfluidics with catalysts, microoptical or mechanical mountings or carrier wafer bonding in microelectronics.