Comparison of MiM performance with various electrodes and dieletric in Cu dual damascene of CMOS MS/RF technology

Abstract

In this paper, we have compared the performance of metal-insulator-metal (MiM) capacitors for different bottom electrode materials including Cu, TaN, and Al in Cu-back-end-of-the-line (BEOL) process. A high-performance and low-defect-density MiM capacitor for mixed-signal and radio frequency (MS/RF) technology based on a 130 nm complementary metal oxide semiconductor (CMOS) process was demonstrated. Q-factor can achieve > 100 for both Cu and Al at 2.4 GHz with 0.7 pF MiM capacitors. TaN showed a low Q-factor (< 60) due to high resistivity. The process incorporates aluminum electrode into Cu BEOL for MiM capacitor with a cost-effective process. The roughness of electro-dielectric interface by a thin aluminum electrode is critical for MiM performance due to field enhancement by roughness of a thin aluminum electrode. We have demonstrated a way to eliminate the roughness effect of thin Al and provide a MiM capacitor with high performance and low defect density. In particular, a method is demonstrated to achieve better matching, leakage, electrical breakdown, and temperature coefficient of capacitance performance for MiM capacitors. (c) 2006 The Electrochemical Society.