CMP Process Optimization for Bonding Applications

Conference: ICPT 2012 - International Conference on Planarization / CMP Technology
10/15/2012 - 10/17/2012 at Grenoble, France

Proceedings: ICPT 2012

Pages: 7Language: englishTyp: PDF

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Balan, Viorel; Seignard, Aurélien; Di Cioccio, Léa (CEA Léti - MINATEC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France)
Scevola, Daniel; Lugand, Jean-François; Rivoire, Maurice (STMicroelectronics, 850 rue Jean Monnet, 38920 Crolles Cedex, France)

This paper presents the optimization of a CMP process optimization in order to obtain very good bendability of copper patterned wafers. Copper planarization allowed obtaining low roughness, very smooth surfaces with practically no dishing for copper lines as wide as 500 µm. Polishing under optimized conditions process allowed highly improved bonding quality, as shown by Scanning Acoustic Microscopy and Transmission Electron Microscopy. Finally, the electrical behavior of direct copper bonded pad was analyzed, and on a 10×10 µm contact pad a specific resistance of rhoc= 0.98 Ω.micrometer2 was measured after a 200deg C annealing for 30 minutes. Keywords: Planarization, TSV, Bonding, 3D, dishing, erosion, design rules