Copper-selective electrochemical filling of macropore arrays for through-silicon via applications
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
Nanoscale Research Letters 2012, 7:375 doi:10.1186/1556-276X-7-375Published: 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 cm−²) was carried out. The conductive paths were then electrically characterized, and a resistance equal to 32 mΩ/copper-filled macropore was determined.