Analysis of Sidewall Damage Layer in Low-$k$ Film Using the Interline Dielectric Capacitance Measurements

We investigate a brief method extracting properties of damage layer in low-k film using the electrical measurement of Cu interconnects. In the electrical measurements, the capacitance measurement is useful for evaluating the damage layer in low-k film because the increase of k-value in low-k film affects directly the change of Cu interconnects capacitance. The interline capacitance including the damage layer can be described by a serial connected parallel-plate capacitor model. The analysis of electromagnetic field shows that the interline capacitance does not correspond to the capacitance of parallel-plate capacitor due to the fringe factors of interline capacitance. We can eliminate the fringe factors of interline capacitance by measuring the capacitances of different line heights and succeed in acquiring the relationship between the thickness and the dielectric constant of sidewall damage layer in low-k film. (C) 2011 The Japan Society of Applied Physics