Laser ultrasound: an inspection tool of soft porous low-dielectric constant films for microelectronic interconnect

摘要

The demand for miniaturization in the microelectronics industry requires that the RC (Resistance-Capacitance) factor be lowered to reduce interconnection delay, crosstalk and power loss. The most promising way to achieve this is by introducing porosity into the dielectric film material. We show that laser-generated surface acoustic waves can successfully and rapidly characterize porosity/density and stiffness of these films. Complementary measurements from X-ray reflectivity and Brillouin light scattering verify our results. We discuss why nanoindentation presents difficulties.