Application of charge based capacitance measurement (CBCM) technique in interconnect process development

The charge based capacitance measurement (CBCM) technique (Chen et al, IEDM p. 69, 1996) was used in order to measure femto-farad level intermetal capacitances between metal lines in different configurations. The results are presented and compared with the calculated numbers using the Rafael simulation program. These structures are used to evaluate the impact of process changes such as the use of low k dielectric on parasitic interconnect capacitance. The parasitic capacitances are determined by using a variety of interconnect structures with varying line width and spacing. Such measurements with low k materials show that the formation of these materials in small narrow spaces may be quite different from that in wide open areas.