Raman spectroscopy is used as a non-contact probe of stress with high spatial resolution in micro-machined silicon structures. The motivation for this work is that reliability or cycle life can be substantially increased by understanding the origin of stress including residual stress. Excessive stresses induced by workmanship shortcomings or design constraints may be addressed by Raman measurements. In microelectronics, stress is known to play a significant role in interconnects which limits reliability, life, and ultimately cost of many circuits. We wish to demonstrate the utility of Raman spectroscopy as a tool for the development and design of silicon microstructures. The equations for a general 2D stress field are discussed. Calibration studies using macro-mechanical fixtures for single crystal silicon specimens under 2D stress field are presented. Our measurements show good agreement with the theoretical values and thus validate the approach taken. Stress maps of conventionally fabricated test structures, laser machined, and polysilicon structures are presented.

Date Published: 7 June 2000
PDF: 9 pages
Proc. SPIE 3933, Laser Applications in Microelectronic and Optoelectronic Manufacturing V, (7 June 2000); doi: 10.1117/12.387547

Published in SPIE Proceedings Vol. 3933:
Laser Applications in Microelectronic and Optoelectronic Manufacturing V
Henry Helvajian; Koji Sugioka; Malcolm C. Gower; Jan J. Dubowski, Editor(s)