High-aspect-ratio deep Si etching of micro/nano scale features with SF6 /H2/ O2 plasma, in a low plasma density reactive ion etching system

摘要

Using three gasese of SF6, O2 and H2, deep vertical etching of silicon substrates in a low plasma density environment is reported. A reactive ion etching (RIE) unit with an operating frequency of 13.56 MHz has been used with plasma power densities below 1 W/cm2. The vertical etching process is based on a sequential method with two sub-sequenes, etching and passivation. High etch rates of the order of 0.7 to 1.5 um/min for deep sub-micrometer features, and aspect ratios about 100 for nano-rods have been achieved.