Semiconductor device and fabricating method of the same

A semiconductor device, comprising:

• a substrate comprising a high voltage region and a low voltage region;
• a first deep trench isolation disposed within the high voltage region, wherein the first deep trench isolation comprises:
• a first deep trench formed by a first trench and a second trench, wherein the first trench is below the second trench, and wherein the first deep trench comprises a first sidewall and a second sidewall, the first sidewall faces the second sidewall, the first sidewall is formed only by a first plane and a second plane, an edge of the first plane connects to an edge of the second plane, a slope of the first plane is different from a slope of the second plane, and the first plane is a sidewall of the first trench;
• and
• a first insulating layer filling in the first deep trench;
• a shallow trench isolation disposed within the low voltage region;
• wherein the shallow trench isolation comprises:
• a trench disposed on the substrate;
• and
• a second insulating layer filling in the trench, wherein a depth of the shallow trench isolation is smaller than a depth of the first deep trench isolation;
• and
• a fin structure protruding from a second surface of the substrate, wherein a depth of the first trench is the same as a height of the fin structure.