Thermal detection of device failure by atomic force microscopy

Device and interconnect electrical failures often occur in the form of short or open circuits which produce hot or cold spots under voltage bias. With the minimum device feature size shrinking to 0.25 μm and less, it is impossible to locate the exact position of defects by traditional thermal or optical techniques such as infra-red emission thermometry, liquid crystals or optical beam induced current. We have used a temperature-sensing probe in an atomic force microscope to locate a hot spot created by a short-circuit defect between the gate and the drain of a Si MOSFET with a spatial resolution of about 0.5 μm. The technique has the potential to produce spatial resolutions in the range of 0.05 μm and efforts are underway to reach this goal.