An apparatus for testing of interruptions / short circuits in the case of capacitive coupled networks in substrates with the use of electron beams

摘要

An E-beam testing system uses the E-beam to test a sample with conductive elements thereon. The system charges conductive elements on the sample. Above the sample and parallel to its upper surface is a stacked pair of parallel extraction grids. One grid is biased positively to accelerate secondary electrons emitted from the sample. The other grid is biased at a voltage to control the angular distribution of secondary electrons passing through the grid. Rectangular double grid sets, tilted with respect to the beam and the sample, are located above and laterally of the sample and the E-beam. Those grids are charged to attract secondary electrons from the sample. Triangular grids between the rectangular grids and a top grid above and parallel to the sample with an aperture therethrough for the E-beam are biased negatively to repel secondary electrons. Below the rectangular and triangular grids is located a cylindrical attraction grid biased positively, coaxial with the E-beam. A method of testing electrical connections and short circuits of conductors on a body of insulating material without physical contact includes the steps of: (a) applying an unfocused flood electron beam with a low current to a broad surface of the body, simultaneously applying a different focused probe electron beam having an energy predetermined to provide a charge of opposite polarity from the flood beam to other areas of the body to be probed, (b) generating an electron beam to cause secondary electron emission from the conductors; and (c) detecting the presence of connections not at a given potential.