MEMS device and manufacturing method thereof

A manufacturing method of a microelectromechanical system (MEMS) device, comprising:

• providing a third substrate having a fourth surface and a fifth surface, and defining multiple first connection areas on the fourth surface;
• forming multiple second grooves and a dividing groove on the fourth surface of the third substrate;
• providing a second substrate having a second surface and a third surface, and defining multiple second connection areas on the third surface;
• bonding the third substrate and the second substrate, wherein the multiple first connection areas are connected with the multiple second connection areas correspondingly;
• defining multiple third connection areas on the second surface of the second substrate;
• dividing the second substrate into a first movable element and a second movable element that are electrically isolated from each other, wherein the first movable element is isolated from the third substrate and one of the second grooves corresponds to the first movable element, and the second movable element is connected with the third substrate via one of the first connection areas and the corresponding connected second connection area;
• providing a first substrate, wherein a first surface thereof includes a first circuit and a second circuit;
• defining multiple fourth connection areas on the first surface of the first substrate;
• bonding the first substrate and the second substrate, wherein the multiple fourth connection areas are electrically connected with the multiple third connection areas correspondingly, the first circuit corresponds to the first movable element, and the second circuit corresponds to the second movable element;
• thinning the third substrate;
• and
• dividing, at the dividing groove, the third substrate into a first cap and a second cap and forming a first groove from the fifth surface of the second cap, wherein
• the first cap corresponds to the first movable element;
• an airtight cavity to sense a pressure variation of the external environment is formed between the second cap and the first substrate;
• a bottom of the first groove of the second cap is connected to the second movable element via one of the first connection areas and the corresponding connected second connection area;
• and
• the second movable element is movable with the second cap by the pressure variation of the external environment.