Portable emission microscope workstation for failure analysis

Abstract

A more efficient portable emission microscope system comprising a cooled CCD camera coupled to microscope optics for detection of photon emissions from integrated circuits. Portability is achieved with a small light tight box and rubber boot combination which are used in conjunction with a probe station or portable stand. The optics are modified to contain an illuminating ring of light emitting diodes for sample illumination prior to or after emission acquisition. Sensitivity is increased by elevating the substrate temperature. In operation, an integrated circuit is enclosed by a rubber boot. An illuminated reference image is then obtained with the LEDs 'on,' and a background image is obtained with the LEDs 'off.' The background image represents illumination noise. The temperature of the circuit is then raised while the circuit is biased. Temperature elevation is accomplished by installing small power resistors at the base of an appropriate burn-in socket. This elevation in temperature causes photon emissions from faults in the circuit. An illumination image is then obtained which captures the photon emissions. The background image is then subtracted from the illumination image to filter the image. Finally, the illumination image is superimposed on the reference image to allow a user to determine the exact location of any failures.