Abstract: An actuator device manufacturing method includes: a preparation step of preparing an actuator device including a support portion, a movable portion, a connection portion, and a metal member disposed such that a stress acts on the metal member when the movable portion oscillates; an oscillation step of oscillating the movable portion for a predetermined time; an acquisition step of acquiring a parameter related to a viscous resistance in a vibration of the movable portion; and a determination step of determining that the actuator device is qualified, when a difference between the parameter acquired in the acquisition step and a reference value corresponding to the parameter at a start of the oscillation step is a predetermined value or more in a direction in which the viscous resistance decreases, and determining that the actuator device is disqualified, when the difference is less than the predetermined value.

Abstract: A method of manufacturing a semiconductor substrate according to an embodiment includes a first step of forming a groove having a bottom surface and a side surface on which scallops are formed by performing a process including isotropic etching on a main surface of a substrate, a second step of performing at least one of a hydrophilic treatment on the side surface of the groove and a degassing treatment on the groove, and a third step of removing the scallops formed on the side surface of the groove and planarizing the side surface by performing anisotropic wet etching in a state where the bottom surface of the recess is present.