Manufacturing method of MEMS sensor

A manufacturing method of a MEMS sensor, comprising the steps of:

• (a) on a substrate, forming a first layer, a second layer on the first layer, and a third layer between the first layer and the second layer;
• (b) after the step (a), by irradiating a first hole formation spot of the second layer with a focused ion beam for a first predetermined time, forming a first hole in the second layer such that the first hole reaches the third layer;
• (c) after the step (b), by irradiating a second hole formation spot of the second layer with a focused ion beam for a second predetermined time, forming a second hole in the second layer such that the second hole reaches the third layer;
• (d) after the step (c), removing the third layer through the first hole and the second hole and then forming a cavity between the first layer and the second layer in such a way as to communicate with the first hole and the second hole;
• and
• (e) after the step (d), forming a sealing film on each of the first hole and the second hole,
• wherein each of the first predetermined time and the second predetermined time is a time in which thermal equilibrium of the second layer is maintainable, and
• wherein, before the step (d), the step (b) and the step (c) are performed repeatedly.