Manufacturing method of high-voltage semiconductor device with increased breakdown voltage

A method for manufacturing a high voltage semiconductor device, comprising:

• providing a semiconductor substrate having a first conductivity type, wherein the semiconductor substrate has an active area;
• forming at least one first isolation structure and at least one second isolation structure in the active area of the semiconductor substrate;
• forming a gate structure on the active area of the semiconductor substrate and at a side of the at least one first isolation structure in a top view of the high voltage semiconductor device, wherein the gate structure extends along a first direction, and in the top view, an end of the at least one second isolation structure is disposed between the at least one first isolation structure and the gate structure in a second direction perpendicular to the first direction;
• and
• forming at least one first drift region in the active area of the semiconductor substrate at a side of the gate structure in the top view, and the at least one first drift region having a second conductivity type complementary to the first conductivity type, wherein a bottom of the at least one first isolation structure and a bottom of the at least one second isolation structure are deeper than a bottom of the at least one first drift region, and in the top view, the at least one first drift region has a Z-shaped part extending from an end of the at least one first isolation structure to the end of the at least one second isolation structure through a space between the at least one first isolation structure and the at least one second isolation structure, such that the at least one first drift region has a zigzag-shaped current path.