Practical application of electron beam testing in LSI and VLSI circuits

The electron beam testing of integrated circuits was studied. Parameters were evaluated for the electron beam acting in a passive way as a nonloading and nondestructive microprobe (voltage measuring method) and in an active way as a micron scaled current source (current impressing mode). The necessary conditions for an absolute determination of integrated circuit internal signals were determined and the required instrumental modifications were realized in the VLSI test system. The testing technique can be extended to passivated devices. Testing via the conductive channel that shorts insulating layers is suited for bipolar and metal oxide semiconductor devices, if radiation damage is excluded by switching off the scanned electron beam at gate oxides. Investigations show that the capacitive coupling voltage contrast may offer an easier alternative.