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Copper-selective electrochemical filling of macropore arrays for through-silicon via applications

Thomas Defforge1*, Jérôme Billoué1, Marianne Diatta1, François Tran-Van2 and Gaël Gautier1

Author Affiliations

1 Université François Rabelais de Tours, GREMAN UMR CNRS 7347, 16 Rue Pierre et Marie Curie, BP 7155, Tours Cedex 2, 37071, France

2 Université François Rabelais de Tours, Laboratoire de Physico-Chimie des Matériaux et des Electrolytes pour l'Energie, E.A. 6299, Parc de Grandmont, Tours, 37200, France

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Nanoscale Research Letters 2012, 7:375  doi:10.1186/1556-276X-7-375

Published: 9 July 2012


In this article, the physico-chemical and electrochemical conditions of through-silicon via formation were studied. First, macropore arrays were etched through a low doped n-type silicon wafer by anodization under illumination into a hydrofluoric acid-based electrolyte. After electrochemical etching, ‘almost’ through-silicon macropores were locally opened by a backside photolithographic process followed by anisotropic etching. The 450 × 450-μm² opened areas were then selectively filled with copper by a potentiostatic electrochemical deposition. Using this process, high density conductive via (4.5 × 105 cm²) was carried out. The conductive paths were then electrically characterized, and a resistance equal to 32 mΩ/copper-filled macropore was determined.

Silicon electrochemical etching; Macropore arrays; Copper electrochemical deposition; Through-silicon via