Measured and Extraction of Coupling Capacitive of Metal Interconnect Layers in VLSI

This paper presents the measurement and extraction of the capacitance for multilayer interconnections in VLSI. The capacitance of the capacitive coupling between interconnect is measured as a function of the varying frequency in order to develop a capacitance versus frequency curve. The multi-fringe structure of interconnect metal1 layer and interconnect metal2 layer(L=400 μm, no. strip=80) with the total perimeter of capacitive coupling is approximately 3.16×10⁴ μm of value and the area is 2.8×10⁴ μm² of value are tested respectively. The line width and line spacing ratio (W/S) of interconnect is varying from 0.9/0.6, 0.9/0.9, 0.9/1.05 and 0.9/1.2 with the measured frequency of 10kHz, 100kHz, 250kHz, 500kHz, 1MHZ and 5 MHz are measured. The coupling of interconnect per unit length at various line spacing as a function of measured frequency of metal1 and metal2 are reported and discussed. The results show that the coupling capacitance per unit length (F/μm) increases as the spacing between adjacent interconnect lines is deceased.