Sidewall Imaging of Microstructures with a Tilted Quartz Tuning Fork (QTF) Force Sensor

Sidewall imaging of micro and nano structures is essential for critical dimensional metrology in the semiconductor industry. Atomic force microscope is an important sidewall imaging instrument due to its three dimensional imaging capability, high accuracy and ultra high resolution. We propose an AFM method for sidewall imaging of high step sidewalls. A tuning fork force sensor with a tungsten tip is tilted at a suitable angle (θ) to access the sidewall. Sidewalls of a micro electromechanical systems (MEME) structure fabricated by deep reactive ion etching (DIRE) process is scanned and sidewall roughness is measured.