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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Multiwavelength Raman characterization of silicon stress near through-silicon vias and its inline monitoring applications
Author(s): Woo Sik Yoo; Jae Hyun Kim; Seung Min Han

Paper Abstract

Characterization of silicon stress near copper (Cu)-filled through-silicon via(s) (TSVs) was demonstrated using high-resolution micro-Raman spectroscopy. For depth profiling of Si stress distribution near TSVs, a polychromator-based, multiwavelength excitation Raman measurement with different probing depths was used. The design concept of the polychromator-based, multiwavelength micro-Raman spectroscopy system, including the importance of the high-spectral resolution and multiwavelength excitation capability in three-dimensional (3-D) Si stress characterization, was described. Silicon stress near Cu-filled TSVs, with various sizes and layouts, was measured and analyzed before and after Cu annealing steps. Main factors impacting Si stress near Cu-filled TSVs are analyzed based on Raman characterization results on various types of TSV structures, layouts, and Cu annealing conditions. Large variations in Si stress in TSV arrays were measured in wafers with poor Cu fill characteristics and in wafers annealed in nonoptimized conditions. The Cu annealing sequence and annealing conditions are found to be significantly important for managing Si stress and the reliability of Cu-filled TSVs. Substantially lower Si stress was measured near Cu-filled TSVs with voids. Multiwavelength micro-Raman spectroscopy can be used as a very effective noncontact, nondestructive, inline TSV process and Si stress monitoring technique.

Paper Details

Date Published: 5 February 2014
PDF: 10 pages
J. Micro/Nanolith. 13(1) 011205 doi: 10.1117/1.JMM.13.1.011205
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 13, Issue 1
Show Author Affiliations
Woo Sik Yoo, WaferMasters, Inc. (United States)
Jae Hyun Kim, KAIST (Korea, Republic of)
Seung Min Han, KAIST (Korea, Republic of)

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