Three dimensional integration and methods of through silicon via creation

A method comprising:

• patterning a photoresist layer on a structure to define an opening and expose a first planar area on a sacrificial substrate layer, the exposed first planar area aligned vertically with a first conductor embedded in the structure;
• etching to the exposed first planar area to form a cavity having a first depth in the structure;
• removing a portion of the photoresist to increase the size of the opening to define a second planar area on the sacrificial substrate layer;
• forming a doped portion in the sacrificial substrate layer, the doped portion aligned vertically with a second conductor embedded in the structure different from the first conductor;
• etching the cavity to increase the depth of the cavity, the first conductor being exposed in response to the etching of the cavity;
• and
• etching the doped portion to expose an underlying planar area, and etching the underlying planar area to increase the planar area and depth of a portion of the cavity, the second conductor being exposed in response to increasing the planar area and depth.