Circuit scanning device and method
AssigneeThe United States of America as represented by the Secretary of the Army
InventorRichard G. Sartore
Life of this patent
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Abstract
A circuit scanning device for use in mapping the lateral dimensions and positions of a conductive layer of an integrated circuit is provided. The device includes a scan control, a scanning electron microscope, an x-ray detector, a map maker, an algorithm storage unit, and an algorithm selector whereby an IC chip is irradiated with an electron beam, which is raster scanned across the IC chip. The x-ray radiation emission is then monitored and the electron beam is adjusted so as to produce an enhanced map of the conductive layers on the IC chip.
Claims1
A method for mapping the overall layout and lateral dimensions of a conductive layer in an integrated circuit having a body of substrate material that includes a surface on which the conductive layer is disposed and having a coating of an insulation material disposed thereover;
- the conductive layer, body of substrate material and insulation material each having different x-ray radiation output in response to electron irradiation inputs, the method comprising the steps of;
- scanning an area of interest on the integrated circuit with a beam of electrons having the energy level thereof adjusted to irradiate both the insulation material and the conductive layer;
- monitoring x-ray radiation synchronously with the scanning, at X-Y pixel locations within the area of interest;
- storing a first map of the x-ray radiation monitored at each X-Y pixel location during the scanning;
- rescanning the area of interest with a beam of electrons having the energy level thereof adjusted to irradiate the insulation material only;
- monitoring the x-ray radiation synchronously with the rescanning, at the X-Y pixel locations;
- storing a second map of the x-ray radiation monitored at each X-Y pixel location during the rescanning;
- subtracting the x-ray radiation monitored at each X-Y pixel location for the second map from the x-ray radiation monitored at each X-Y pixel location for the first map, to derive a third map from the x-ray radiation that relates to only the conductive layer at each X-Y pixel location.
Dependencies are inferred from the claim text.