Inertial sensor and method for forming the same

An inertia sensor and a method for forming the inertial sensor, from bottom of the inertia sensor to top of the inertia sensor, the inertia sensor successively comprising:

• a first substrate, wherein the first substrate has a circular shape;
• a medium layer stacked on the first substrate;
• a first electric-conductive layer having a circular shape stacked on the medium layer, wherein first openings are formed in the first electric-conductive layer, and the first openings are spaced apart from one another and are arranged along a radial direction of the first electric-conductive layer;
• second electric-conductive layers having a circular shape, wherein the second electric-conductive layers are bonded to the first electric-conductive layer through bonding structures from bottom to top;
• wherein a gap is formed between adjacent ones of the second electric-conductive layers, and adjacent ones of the electric-conductive layers are connected to each other by a connection part;
• and wherein second openings are formed in each of the second electric-conductive layers, and the second openings are spaced apart from one another and are arranged along a radial direction of each of the second electric-conductive layers;
• and
• a second substrate covering the first substrate, wherein a closed space is formed between the second substrate and the first substrate and the second substrate has a circular shape;
• and wherein the method comprises:
• forming one of the second electric-conductive layers on the second substrate, and forming the second openings in the second electric-conductive layer;
• depositing a sacrificial layer on the one of the second electric-conductive layers;
• forming another one layer of the second electric-conductive layers on the sacrificial layer, and forming the second openings in the another one of the second electric-conductive layers;
• connecting the one layer of the second electric-conductive layers and the another one layer of the second electric-conductive layers with the connection part;
• forming a second bonding layer on the second electric-conductive layers;
• forming the medium layer and the first electric-conductive layer on the first substrate, and forming the first openings in the first electric-conductive layer;
• forming a first bonding layer on the first electric-conductive layer;
• removing the sacrificial layer;
• and
• bonding the first bonding layer and the second bonding layer together at a high temperature, and forming a closed space between the second substrate and the first substrate;
• wherein the connection part comprises first connectors, the first connectors are spaced apart from one another and are arranged along a radial direction of each of the second electric-conductive layers, and two ends of each of the first connectors are connected to two adjacent ones of the second electric-conductive layers;
• wherein positions of the first connectors correspond to positions of the bonding structures, respectively.