Methods for forming interconnects in microelectronic workpieces and microelectronic workpieces formed using such methods are disclosed herein. One embodiment, for example, is directed to a method of processing a microelectronic workpiece including a semiconductor substrate having a plurality of microelectronic dies. The method can include forming a first opening in the substrate from a back side of the substrate toward a front side and in alignment with terminals of the dies. The first opening separates an island of substrate material from the substrate. The method can also include depositing an insulating material into at least a portion of the first opening, and then removing the island of substrate material to form a second opening. In several embodiments, the method may include constructing an electrically conductive interconnect in at least a portion of the second opening and in electrical contact with the terminal.