A mechanical surface adhesive using micromachined silicon structures

Abstract

The authors have developed a velcro-like mechanical fastening system, capable of joining two surfaces together without chemical bonding, using silicon micromachining techniques. Using conventional processes, microscopic structures are fabricated that mechanically interlock with matching, identically processed substrates. The interlocking is accomplished by the elastic deflection of SiO₂ flanges angled in such a way that the bond is permanent. Each structure is 18 mu m*18 mu m by 12 mu m high; there are approximately 200000 individual structures per cm² of substrate, resulting in a strong bond. Preliminary measurements show the tensile strength of the bond to be in excess of 380 kPa (55 psi); the shear strength is similarly high. Applications for this 'mechanical adhesive' technology include medical uses (i.e. joining tissues), integrated circuit packaging, and interfacing of microdynamic machines to the macroscopic world.