Abstract: An apparatus and method for providing an etching gas source for etching one or more microstructures located within a process chamber. the apparatus has a gas source supply line attached to a gas source and one or more chambers for containing an etching material. In use, the etching material is transformed into an etching material vapor within one or more of the chamber and the gas supply line provides a supply of carrier gas to the etching material vapor and also supplies the etching material vapor transported by the carrier gas to the process chamber. Advantageously, the apparatus of the invention does not require the incorporation of any expansion chambers or other complicated mechanical features in order to achieve a continuous flow of etching gas.