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Copper deposition using wet chemistry. A new way : Organometallic chemistry for microelectronics

Clément Barriere 1,2Pierre Fau 1Olivier Margeat 1Vincent Collière 1Gilles Alcaraz 1Christine Anceau 2Jean-baptiste Quoirin 2Bruno Chaudret 1

1. Laboratoire de Chimie de Coordination (LCC), 205 route de Narbonne, Toulouse 31077, France
2. STMicroelectronics, Tours 37071, France

Abstract
Metallic Copper is currently one of the most used materials in microelectronics for the preparation of conducting lines. This interest comes from its good electric conductivity and its good resistance to electromigration1 . Several chemical and physical methods are used to create these deposits. Physical methods used are mostly PVD2 technics (Physical Vapor Deposition) as sputtering or vacuum evaporation. The most employed chemical ones are electrolysis and electroless3-4, two methods using mild chemical conditions. However, both require a pre-metalized subtrate to initiate the reaction. Objective of our work is to form homogeneous and adherent layers of copper on silicon wafer substrates with an oxide layer on surface. We have chosen two main ways. First one uses nanoparticles in solution coming from an organometallic synthesis. We will detail here synthetic roads leading to copper nanoparticules of controlled size and shape. These particles can be deposited on a substrate by spin-coating or ink-jet. The second way is to realize the deposit on the substrate in situ during the decomposition reaction of the organometallic complexes. Thin films are obtained after this first step, which can be followed by an electroless deposit to increase the thickness. All deposits are characterized by scanning electron microscopy, X-ray diffraction and profilers. An electric characterization is also done.

1J. Li, T.E. Seidel and J.W. Mayer, Copper based metallization in ULSI structures. MRS Bull. XIX 8 (1994), p. 15.
2R. Jagannathan and M. Krishnan, Electroless plating of copper at a low pH level, IBM J. RES. DEVELOP., 37, (1993), 117-123.
3S.H.Y. Lo, Y.-Y. Wang, C.-C. Wan, Synthesis of PVP stabilized Cu/Pd nanoparticules with citrate complexing agent and its application as an activator for electroless copper deposition, J. Coll. Int. Sci, 310 (2007), 190-195.

 

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Related papers

Presentation: Oral at E-MRS Fall Meeting 2007, Symposium B, by Clément Barriere
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-06-27 15:31
Revised:   2009-06-07 00:44