| 摘要 |
<p>The method comprising covering metal test pads (4) of an integrated circuit chip-to-test (11), with a photon-transmissive passivation layer (2) susceptible to photon assisted tunneling, covering the layer (2) with a thin conductive photon-transparent overlayer (3), and then accessing the test pads through the passivation layer and conductive overlayer, by a pulsed laser to provide voltage-modulated photon-assisted tunneling through the insulation layer, to the conductive overlayer as an electron current, and detecting the resulting electron current, thus providing a nondestructive test of integrated circuits. The passivation, normally present to protect the integrated circuit, also lowers the threshold for photoelectron emission. The conductive overlayer acts as a photoelectron collector for the detector. A chip-to-test which is properly designed for photon assisted tunneling testing has test sites accessible to laser photons even though passivated. Such a chip-to-test may be nondestructively tested in air at one or several stages of its processing, without the sacrifices of mechanical probing or of bringing test sites out to output pads.</p> |
