Atomic force microscopy and signal acquisition via buried insulator

The present invention relates generally to semiconductor devices and their fabrication and, more particularly, to testing and defect analysis of semiconductor dies signal acquisition. Analysis of a semiconductor die having silicon-on-insulator (SOI) structure is enhanced by accessing the circuitry within the die from the back side without necessarily breaching the insulator layer of the SOI structure. According to an example embodiment of the present invention, a semiconductor die having a SOI structure and a backside opposite circuitry in a circuit side is analyzed. An atomic force microscope is scanned across a thinned portion of the back side. The microscope responds to an electrical characteristic, such as a logic state, coupled from circuitry via the insulator portion of the die over which the microscope is being scanned. The response of the microscope to the die is detected and used to detect an electrical characteristic of the die.