Stress measurement in thin films applied in technology of integradted circuits

• Grant number: 92/03452-1
• Support Opportunities: Research Projects - Thematic Grants
• Start date: May 01, 1993
• End date: December 31, 1996
• Field of knowledge: Engineering - Electrical Engineering - Electrical Materials
• Principal Investigator: João Antonio Zuffo
• Grantee: João Antonio Zuffo
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant(s): 96/01329-9 - Development of a cluster tool and analysis of deposition oxide by teos/o2 pecvd., AR.EXT

Abstract

In this project, we studied the stress influence in the quality of TEOS PECVD silicon oxide, titanium silicides, silicon nitride and poly silicon thin films. The stress versus temperature analysis in the TEOS PECVD silicon oxide showed hysteresis that indicate a variation in the intrinsic stress due to structural modification in the film. The deposition process pressure has a small influence in the intrinsic stress inside the used narrow process window. When we use high RF power (450 W), during the deposition process, the stress increase with the oxygen flow. The stress also increase when higher RF power is used. This behavior can be due to the higher ion bombardment and by cross linking effects in the interface Si/SiO2 which introduce the intrinsic stress. In the study performed in titanium silicides formation, the TiSi2 C49 phase formation cause a increase in the compressive stress and this reaction occur faster in the Ti over poly silicon process than in the Ti over mono silicon (100) substrates. Moreover the TiSi2 C49 formation bear a stress relaxation process before the TiSi2 C54 final formation. The stress measurements performed in the silicon nitride thin films deposited by LPCVD showed a high stress which means that is not possible to use thicker films. In the poly silicon thin films deposited by LPCVD, the stress is very low and no changings with the process parameters were observed. (AU)