Advanced glass etching method exhibiting the controllable etch stop using metal etchant

Abstract

The limitations of conventional glass etching methods are a bottleneck in the further development of glass as a substrate, which is critically important in micro- and nanoelectromechanical systems. In this paper, we describe a new wet etching method for Pyrex glass using a metal etchant. An aluminum pattern is deposited on the Pyrex and then subjected to thermal and electrostatically induced interdiffusion to form an aluminum-rich layer of controllable thickness in the glass, which can then be etched with an aluminum etchant. Because the underlying glass acts as an etch stop, no etching mask is required and the etching depth is effectively controlled by the electric field strength. This method can be used for fabricating glass nanochannels and nanodepth structures, and also in processes incompatible with hydrogen fluoride.