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Proceedings Paper

3D through silicon via profile metrology based on spectroscopic reflectometry for SOI applications
Author(s): O. Fursenko; J. Bauer; S. Marschmeyer
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Paper Abstract

Through-silicon via (TSV) technology is a key feature for 3D circuit integration. TSVs are formed by etching a vertical via and filling them with a conductive material for creation of interconnections which go through the silicon or silicon-on-insulator (SOI) wafer. The Bosch etch process on Deep Reactive Ion Etching (DRIE) is commonly used for this purpose. The etch profile defined by the critical dimensions (CDs) at the top and at the bottom, by the depth and by the scallop size on the sidewall needs to be monitored and well controlled.

In this work a nondestructive 3D metrology of deeply-etched structures with an aspect ratio of more than 10 and patterns with lateral dimensions from 2 to 7 μm in SOI wafer is proposed. Spectroscopic reflectometry in the spectral range of 250-800 nm using a production metrology tool was applied. The depth determinations based on different algorithms are compared.

The Pearson correlation coefficient between measured and calculated reflection is suggested as the most appropriate method. A simple method for top CD evaluation is proposed by the measurement of reflection and using the polynomial approximation of reflection versus TSV filling coefficient which is determined as ratio of CD to pitch. The 3D RCWA simulations confirm this dependence.

Paper Details

Date Published: 26 April 2016
PDF: 6 pages
Proc. SPIE 9890, Optical Micro- and Nanometrology VI, 989015 (26 April 2016); doi: 10.1117/12.2227651
Show Author Affiliations
O. Fursenko, IHP GmbH (Germany)
J. Bauer, Technische Hochschule Wildau (Germany)
S. Marschmeyer, IHP GmbH (Germany)

Published in SPIE Proceedings Vol. 9890:
Optical Micro- and Nanometrology VI
Christophe Gorecki; Anand Krishna Asundi; Wolfgang Osten, Editor(s)

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