University System of Maryland

Christopher J Lobb

Frederick Charles Wellstood

Matthew Edward Kenyon

A system, method, and computer program product are provided for scanning objects such as computer chips. A near-field scanning Single Electron Transistor (SET) is used to detect features of the object. In particular, the SET detects variations in an electric field surrounding or emanating from the object. The variation in the field may be associated with an irregularity in the object, such as an open in the circuitry of a chip. In the case of a chip or a multi-chip module, a voltage is applied to the line containing the suspected open. If an actual open is present, the open will be manifested in an irregularity in the electric field associated with the line. The SET detects the irregularity in the field. For the SET to operate, a sufficiently cold operating temperature is maintained for the SET. A very low (cryogenic) temperature allows the use of a larger, more sensitive SET. Scanning SETs are known in the literature, but in such systems the object to be scanned must also be at cryogenic temperatures. In the invention described herein, the object to be scanned can be left at a temperature in its normal environmental temperature range. This temperature range is referred to hereinafter as the ambient temperature range of the object. A chip, for example, typically operates in an ambient temperature range that includes room temperature. Data from the SET indicating irregularity in the electric field can be used to derive readout data, which can in turn be used to produce an image of the object scanned.

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Washington, DC, United States of America

Christopher J Lobb