Abstract: A method of forming a passage in a substrate for a MEMS module is disclosed to include the steps of respectively forming a first support layer and a second support layer in a first space and a second space, which are respectively formed in a bottom side and a top side of a substrate by etching, by injection molding to define a sacrifice portion between the first and second support layers, and removing the sacrifice portion from the substrate by etching to form a passage defined between the first support layer and the second support layer in the substrate with two ends in communication with ambient atmosphere.