Microphone, manufacturing method and control method thereof

A method of manufacturing a microphone, comprising:

• forming an insulating layer on an upper surface of a substrate;
• forming a plurality of sound apertures in the insulating layer;
• forming a diaphragm and a displacement adjusting layer on an upper surface of the insulating layer;
• forming a sacrificial layer to cover the diaphragm and the displacement adjusting layer on the upper surface of the insulating layer;
• forming a fixing layer on an upper surface of the sacrificial layer;
• forming a plurality of apertures by etching the fixing layer;
• exposing an electrode pad of the diaphragm by etching a portion of the sacrificial layer;
• forming a sound inlet by etching a center portion of the substrate;
• and
• removing a portion of the sacrificial layer,
• wherein the forming of the displacement adjusting layer includes forming a first adjusting layer adjacent to a circumference of the diaphragm;
• and forming a second adjusting layer along a circumference of the first adjusting layer spaced apart from the first adjusting layer,
• wherein the plurality of displacement adjusting units are formed between the first adjusting layer and the second adjusting layer, and
• wherein a plurality of first protruding steps that extend from the first adjusting layer to an external side are alternately disposed with a plurality of second protruding steps that extend from the second adjusting layer to an internal side, to form the plurality of displacement adjusting units.

A method of controlling a microphone, which includes a fixing layer, a diaphragm, and a plurality of displacement adjusting units formed between a displacement adjusting layer disposed in a circumference of the diaphragm, the method comprising:

• comparing, by a processor, an input acoustic pressure measured based on a capacitance value, which is varied by a sound, between the diaphragm and the fixing layer with a predetermined acoustic pressure;
• and
• increasing, by the processor, a voltage applied to the displacement adjusting unit when the input acoustic pressure is greater than the predetermined acoustic pressure as a result of the comparison,
• wherein hardness of the diaphragm is adjusted based on a size of the voltage applied to the displacement adjusting unit.