Characteristics of inverted pyramidal microdischarge devices operating in CHF&lt;inf&gt;3&lt;/inf&gt; and CHF&lt;inf&gt;3&lt;/inf&gt;/Ar for maskless microplasma etching

L Wen,H Wang,L L Cheng,L W He,Z Yuan,J R Chu

doi:10.1109/transducers.2011.5969579

Abstract

In the SPM-based microplasma etching system proposed in our previous work, the stable discharge performance of microplasma device in reactive gases is the foundation of the following maskless scanning etching. In order to realize microplasma etching of SiO 2 or Si 3 N 4 , CHF 3 or CHF 3 /Ar mixtures is chosen as the operating gas. Although discharge characteristics of microcavity plasma devices in rare gases have been widely studied, the microdischarge characteristics in CHF 3 reactive gases have been rarely reported up to date. In this paper, the inverted pyramidal microdischarge devices are successfully fabricated with good quality. Experiment results show that the devices can discharge stably in CHF 3 and CHF 3 /Ar mixtures under dc excitation. The voltages-current (V-I) curves of micrplasma devices in CHF 3 and CHF 3 /Ar gas mixtures exhibit negative differential resistance in a classical hollow cathode discharge mode. The pd scaling values ( p and d are the CHF 3 gas pressure and characteristic dimension of the microdischarge devices, respectively) for minimum ignition voltage are observed about 0.4Pa m. The results of this paper verify the feasibility of microplasma maskless etching of SiO 2 or Si 3 N 4 and lay a foundation for upcoming experiments of SiO 2 or Si 3 N 4 maskless etching.

Full Text