Abstract: A method for creating at least one cavity in a semiconductor substrate including the steps of: (a) partially ablating the semiconductor substrate from the top side with a laser to form a trench in the semiconductor substrate surrounding a cross section of the semiconductor material having the desired shape, (b) machining the backside of the semiconductor substrate partially ablated in step (a) to reduce the semiconductor substrate to a final thickness that is equal to or less than the laser ablation depth to form a plug of semiconductor material unattached to a remainder of the semiconductor substrate; and (c) removing the plug of semiconductor material from the semiconductor substrate to form the at least one cavity with cross section of desired shape extending through the semiconductor substrate.