Highty Selective Contact Hole Etching Using Electron Cyclotron Resonance Plasma

概要

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The SiO_2 etching process is one of the most significant processes in ultra-large-scale integration (ULSI) fabrication. In order to obtain fine contact holes, it is necessary to achieve both highly selective etching of SiO_2 over other materials and non-reactive ion etch (non-RIE) lag. We investigated the etching characteristics and the effect of O_2 addition in C_4F_8+O_2 plasma using electron cyclotron resonance (ECR) discharge. In C_4F_8+O_2 plasma, we can obtain dense fluorocarbon films at low pressure, and films are more durable against ion bombardment than at high pressure. This film enables the suppression of O atoms to the Si surface, and the achievement of high SiO_2-to-Si selectivitv. By additional O_2, dissociation of high-mass species such as C_2F_5 proceeds, and at about 20%O_2, low-mass species, such as C, CF, and CF_2, increase. Thus we can obtain high SiO_2-to-Si selectivity and high-aspect-ratio fine contact holes.
社団法人応用物理学会の論文
1995-04-30