High-performance ultralow dielectric constant carbon-bridged mesoporous organosilica films for advanced interconnects

Abstract

Mesoporous organosilica (MO) films are prepared using precursor 1,2-bis(triethoxysilyl)ethane (BTEE) and porogen template poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (P123). The effects of annealing temperature, P123/BTEE molar ratio, and moisture adsorption on the characteristics of the MO films are investigated. It is indicated that MO films prepared at a P123/BTEE molar ratio of 0.016 display the lowest dielectric constant (κ) of 1.80, a small dissipation factor of 0.0068 at 100 kHz, an extremely low leakage current density of 2.01 × 10⁻⁹ A cm⁻² at 0.5 MV cm⁻¹, a modulus (E) of 6.27 GPa, and a hardness (H) of 0.58 GPa. Following moisture adsorption, the κ value increases by ∼12%. However, ultraviolet treatment significantly reduces the extent of increase of the κ value to 4%. The films maintain an ultralow κ value of ∼2.0 and a very low leakage current density of 1.7 × 10⁻⁹ A cm⁻² at 0.5 MV cm⁻¹. Following annealing at 500 °C, the superior performance of the MO films is demonstrated by their κ value of ∼1.92, leakage current density of 7.08 × 10⁻⁹ at 0.5 MV cm⁻¹, and improved E of ∼9.1 GPa and H of ∼0.8 GPa. Such MO films are very promising for advanced interlevel insulators.