Reactive ion etching and OES endpoint detection of AlCu thin film

Patterning of AlCu alloy thin films is a key technology in MEMS fabrication. In this paper, reactive ion etching (RIE) process of Al-1%Cu films was described using BCl3 and Cl2 as etching gases and N2 and CH4 as neutral gases. A four-step process was presented to meet the etching requirements using BCl3, Cl2, N2 and CF4 as process gases. Optical emission spectroscopy (OES) was used to monitor the state of the plasma in real time. The etching endpoint was detected by detecting the spectral intensity change in the wavelength range of 395 ~ 400nm.

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