Abstract: An electrical beam switch for interconnection between a plurality of inputs and outputs and includes a two-dimensional array of electrically charged particle emitters and an array of detectors facing the emitter array for receiving charged particles from various of the emitters. X and y electrical deflectors are positioned adjacent each of the emitters for directing the charged particles from each of the emitters to a selected one or more of the detectors. A screen lens may be positioned adjacent the array of detectors for focusing the directed beams on to the selected detector.

Abstract: An electron beam testing apparatus for applying an electron beam to parts of an electronic component and measuring the secondary electrons released from the part including a secondary electron collector having a plurality of vertically extending screens with a detector positioned adjacent one of the screens. A different voltage is applied to each of the screens of the collector for collecting the secondary electrons over a large area. The apparatus may include a combination blanking and Faraday cup for metering the electron beam current when it is blanked. The apparatus may also be used to measure net work capacitance by measuring the time required to charge a network to a predetermined voltage.

Abstract: An electron beam method and apparatus, for writing patterns, such as on semiconductor wafers, in which the writing field is divided into a large number of overlapping subfields with a predetermined periodicity. Subfield to subfield moves are made in a stepped sequential scan, such as raster, while patterns, within a subfield, are addressed using vector scan and written using a sequential scan. Significant improvement in throughput results by the use of this electron beam method and apparatus which preferably employs magnetic deflection for the sequential scanning the subfields and electric deflection for vector scanning within the subfield.

Abstract: A method and apparatus is described for performing automatic overlay measurements on wafers utilized in semiconductor manufacturing. The overlay measurements are made at selected sites on a given wafer where a single bar pattern has been overlaid over a double bar pattern. The position of the single bar center line with respect to the center line between the double bars is a direct indication of the overlay error of the two patterns. The overlay error is measured in both the X and Y dimensions and is utilized to monitor the overlay error or to produce statistics and correlations to system parameters so that the sources of overlay errors may be identified and the errors eliminated or minimized on subsequent wafers being processed.

Abstract: A beam of charged particles has its alignment and brightness alternately controlled in accordance with the current of the beam. The measurements of the current and any corrections for alignment or brightness are made when the beam is not applied to a target.

Abstract: circuit for controlling the electron discharge from a cathode, of an electron discharge device, which provides a control voltage signal, proportional to the cathode current, for comparison with a reference value to provide a correction bias to a grid interposed between the cathode and an anode.