Patterned metal interconnections were subjected to a non-destructive noise measurement procedure involving a constant rate temperature cycle (heating followed by cooling) at relatively low test current densities. Evidence is presented which suggests that the effects of stress and electromigration on the films caused distinctly different signatures to appear in their excess noise waveforms. When current densities and temperatures were low, electromigration was minimized and the excess noise (in excess of the noise predicted by fundamental effects) was due to the presence of grain boundaries and stresses present in the film. As the temperature of the films was increased, material flow changes the time domain waveforms towards a stationary fluctuation which departed from fundamental 1/f behaviour (with alpha >> 1). On cooling, the films also exhibited fluctuations with steep frequency dependences. Here, however, the films exhibited non-stationary time domain behavior in the form of abrupt changes in resistance as the tensile stress was increased during the cooling cycle. The cycle was then repeated to yield nearly identical results suggesting that little damage to the interconnections occurred during the measured procedure.