Features of silicon deep plasma etching process at 3D-TSV structures producing

Abstract

In this work experimental research results of silicon deep plasma etching features during 3D-TSV structure producing in inductively coupled plasma are presented. Silicon etching operational parameters influence (inductor RF power, working gas consumption) on process technological characteristics (Si etching rate, selectivity and etching profile) is investigated. Wherein passivation stage’s operational parameters were not changed and were constant. It is shown that microroughness in the form of microneedles and column structures can be formed on the bottom of formed structures at low RF power values; full stop of Si etching process can be also possible. It has been revealed that during polymerization stage fluorocarbon film’s deposition rate increase is observed on structure’s inclined surface in comparison with film’s deposition rate on vertical surfaces. At the same time fluorocarbon film’s deposition rate on the bottom of trench is higher than in inclined surface of the structure. Silicon surface after deep plasma etching process is studied. Fluorocarbon film’s adhesion to silicon and silicon oxide ability is researched. It is demonstrated that adhesion on test samples has small values or missing.