Novel low temperature pressure-assisted bonding technology

We introduce a new low temperature bonding technology to assemble two microstructured glass substrates for the realization of microchannels for miniaturized chemical analysis applications. To realize the microchannels, we introduce, besides the well-known HF-etching technology, two simple alternative methods, namely sawing and micro-powder blasting. After proper cleaning of the two glass surfaces, direct bonding is obtained just by exposing the glass stack to a high pressure (up to 50 MPa) in the 100-200 °C temperature range. At these low temperatures, we obtain bonding strengths as high as 10 MPa, comparable to the best values reported in literature. As a possible mechanism for this strong bonding, we propose the pressure-induced enhancement of the bonding contact surface.