Optimum inductively coupled plasma etching of fused silica to remove subsurface damage layer

• Published in: Applied surface science Vol. 355; pp. 1180 - 1185
• Main Authors: Jiang, Xiaolong, Liu, Ying, Liu, Zhengkun, Qiu, Keqiang, Xu, Xiangdong, Hong, Yilin, Fu, Shaojun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2015
• Subjects: Chambers; Damage; Devices; Etching; Fused silica; Inductively coupled plasma; Inductively coupled plasma etching; Optimization; Plasma induced surface damage; Subsurface damage; Surface roughness; Subsurface damage; Plasma induced surface damage; Inductively coupled plasma etching; Fused silica
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.07.168

•SSD layer of fused silica is removed by ICP etch with surface roughness of 0.23nm.•Metal contamination is successfully avoided by employing an isolation device.•Unique low-density plasma induced pitting damage is discovered and eliminated.•Lateral etching of SSD is avoided due to the improvement of etching anisotropy. In this work, we introduce an optimum ICP etching technique that successfully removes the subsurface damage (SSD) layer of fused silica without causing plasma induced surface damage (PISD) or lateral etching of SSD. As one of the commonest PISD initiators, metal contamination from reactor chamber is prevented by employing a simple isolation device. Based on this device, a unique low-density pitting damage is discovered and subsequently eliminated by optimizing the etching parameters. Meanwhile etching anisotropy also improves a lot, thus preventing the lateral etching of SSD. Using this proposed technique, SSD layer of fused silica is successfully removed with a surface roughness of 0.23nm.