Semiconductor device and manufacturing method thereof

A semiconductor device, comprising:

• a semiconductor substrate comprising a first element and a second element, wherein a first atomic ratio of the second element to the first element near an active side of the semiconductor substrate is less than a second atomic ratio of the second element to the first element near a back side of the semiconductor substrate;
• devices disposed at the active side of the semiconductor substrate;
• and
• an interconnect structure disposed over the active side of the semiconductor substrate and electrically coupled to the devices.

A manufacturing method for a semiconductor device, comprising:

• forming an insulating region inside a semiconductor substrate, wherein the insulating region extends along a first direction, and the semiconductor substrate comprises device regions and a sacrificial region surrounding the device regions;
• forming an insulating via in the sacrificial region of the semiconductor substrate and connected to the insulating region, wherein the insulating via extends along a second direction substantially perpendicular to the first direction;
• forming devices and an interconnect structure over the semiconductor substrate and in the device regions, wherein the interconnect structure is electrically coupled to the devices;
• forming a window in the sacrificial region of the semiconductor substrate to expose the insulating via;
• removing the insulating via and the insulating region through the window;
• and
• separating the device regions from one another.