Title: Performance evaluation of cleaning solutions enhanced with tetraalkylammonium hydroxide substituents for post-CMP cleaning on poly-Si film
Authors: Pan, TM
Lei, TF
Ko, FH
Chao, TS
Liaw, MC
Lee, YH
Lu, CP
Department of Electronics Engineering and Institute of Electronics
Issue Date: 1-Jun-2002
Abstract: The cleaning solutions augmented with tetraalkylammonium hydroxides (TAAHs) with various chain-lengths of hydrocarbon substituents were developed for post-poly-Si chemical mechanical polishing (CMP) cleaning. The cleaning performance with respect to particle, organic, and metal removal as well as surface roughness was evaluated for a series of 3% NH4H solutions dosed with 0.26 M of a TAAH and 100 ppm of ethylenediaminetetraacetic acid (EDTA). The experimental results demonstrated that the cleaning solutions enhanced with these surfactants (TAAH) and a chelating agent (EDTA) achieved significantly better removal efficiencies of particle and metal impurities than the control solution containing 3% NH4OH only. A conceptual model involving surface adsorption and double-layer formation was used to postulate the aqueous-phase surface interactions between the tetraalkylammonium cations and the poly-Si surface, and to explain the removal mechanisms of particle and metal impurities from the surface. The improved electrical properties (current density-electric field and charge-to-breakdown characteristics) of the post-CMP capacitor after cleaning further demonstrated the reliability and feasibility of the proposed cleaning recipes. (C) 2002 The Electrochemical Society.
URI: http://dx.doi.org/10.1149/1.1474435
ISSN: 0013-4651
DOI: 10.1149/1.1474435
Volume: 149
Issue: 6
Begin Page: G336
End Page: G342
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