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E-Beam Testing of Printed Circuit Conductors

IP.com Disclosure Number: IPCOM000061502D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Bard, SL: AUTHOR

Abstract

Testing of printed circuit (PC) conductors on a substrate by a scanning electron beam probe is simplified by using a "pull-up" resistor network and multiplexer technique. A scanning electron beam 1, which may be generated by a scanning electron microscope (SEM), is deflected to one end of a printed circuit conductor 3 while the other end of the conductor is connected to a voltage source +V, via a contact 3 and one of a plurality of "pull-up" resistors 5. All of the conductors except the selected one are held to a predetermined voltage level, e.g., positive while the selected conductor is connected to a different predetermined voltage level, e.g.

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E-Beam Testing of Printed Circuit Conductors

Testing of printed circuit (PC) conductors on a substrate by a scanning electron beam probe is simplified by using a "pull-up" resistor network and multiplexer technique. A scanning electron beam 1, which may be generated by a scanning electron microscope (SEM), is deflected to one end of a printed circuit conductor 3 while the other end of the conductor is connected to a voltage source +V, via a contact 3 and one of a plurality of "pull-up" resistors 5. All of the conductors except the selected one are held to a predetermined voltage level, e.g., positive while the selected conductor is connected to a different predetermined voltage level, e.g., negative, by closing the appropriate circuit via a conventional multiplexer, here illustrated schematically by the plurality of switches 7, which, when closed, connect the associated conductor to -V. The incident electron beam 1 generates a secondary emission electron signal which is detected by a suitable detector 9. The signal has a much higher value when incident electrons strike conductors connected to the negative voltage, while the signals occurring during scanning of conductors connected to the positive voltage will have a distinctly lower value, thus making it easy to determine if a conductor is not continuous, or if it is shorted to another conductor.

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