Test fixture for future integration

The present invention relates to semiconductor device assemblies, and more particularly to techniques for analyzing and debugging circuitry as may be applied, for example, to a flip-chip bonded integrated circuit. According to one aspect of the disclosure, the present invention provides methods and arrangements for testing a flip chip SOI semiconductor device after the back side of the chip has been thinned to expose a selected region in the substrate. For some chips, thinning removes substrate material useful for drawing heat away from the internal circuitry when the circuitry is running at high speeds. To compensate for this material loss, a special test fixture having a passive, corrosion-resistant heat-dissipating device is arranged to draw heat from the device.