Electroless Plating of Copper on Metal-Nitride Diffusion Barriers Initiated by Displacement Plating

Copper is deposited on TaN and WN barrier layers by electroless plating without the need for activation preprocessing when substrates are (i) pretreated by wet chemical etching to remove surface oxides, and (ii) immersed in an electroless Cu plating solution containing glyoxylic acid as a reducing agent. Electrical potential measurements indicate that the redox potentials of TaN and WN in the plating solution are lower than that of copper, driving displacement plating of Cu in the initial stage of deposition. The adhesion between electroless-plated Cu and the TaN barrier layer after annealing is 0.11 kgf/cm as determined by a peeling test, which is sufficient for reliability during chemical mechanical polishing. A damascene Cu interconnect was successfully fabricated without delamination and exhibited an electrical resistivity of 2.2 μΩ cm after annealing for a 0.42 μm wide interconnect track. These results indicate that the proposed electroless process is suitable for the formation of a Cu seed layer prior to electrodeposition for the fabrication of ultralarge scale integrated interconnects. © 2003 The Electrochemical Society. All rights reserved.

[1]  T. Osaka,et al.  Fabrication of Nickel Dots Using Selective Electroless Deposition on Silicon Wafer , 1998 .

[2]  J. Patterson,et al.  Selective electroless copper metallization on a titanium nitride barrier layer , 1997 .

[3]  Y. Shacham-Diamand.  Electroless Copper Deposition Using Glyoxylic Acid as Reducing Agent for Ultralarge Scale Integration Metallization , 1999 .

[4]  J. Yeh,et al.  Displacement Activation of Tantalum Diffusion Barrier Layer for Electroless Copper Deposition , 2001 .

[5]  X. Jiang,et al.  Electroless copper metallisation of titanium nitride , 1995 .

[6]  T. Osaka,et al.  Effect of oxidized silicon surface on chemical deposition of nickel on n-type silicon wafer , 1999 .

[7]  Direct electroless plating of Cu on barrier metals , 2002, Proceedings of the IEEE 2002 International Interconnect Technology Conference (Cat. No.02EX519).

[8]  Mao-chieh Chen,et al.  Passivation of Cu by Sputter‐Deposited Ta and Reactively Sputter‐Deposited Ta‐Nitride Layers , 1998 .

[9]  J. Yeh,et al.  Electroless Copper Deposition for Ultralarge-Scale Integration , 2001 .

[10]  L. Nagahara,et al.  The influence of hydrofluoric acid concentration on electroless copper deposition onto silicon , 1992 .

[11]  Jui-Chang Chuang,et al.  Properties of thin Ta–N films reactively sputtered on Cu/SiO2/Si substrates , 1998 .

[12]  Ho-Kyu Kang,et al.  Electroless Cu for VLSI , 1993 .

[13]  T. Ohmi,et al.  Adhesion improvement of electroless copper to a polyimide film substrate by combining surface microroughening and imide ring cleavage , 2002 .

[14]  J. Lee.  A new concise inorganic chemistry , 1977 .

[15]  J. Lee.  Concise inorganic chemistry , 1965 .

[16]  Panayotis C. Andricacos,et al.  Damascene copper electroplating for chip interconnections , 1998, IBM J. Res. Dev..

[17]  L. Nagahara,et al.  Effects of HF solution in the electroless deposition process on silicon surfaces , 1993 .

[18]  G. G. Peterson,et al.  Low-temperature chemical vapor deposition of tantalum nitride from tantalum pentabromide for integrated circuitry copper metallization applications , 1999 .

[19]  TodaFumio,et al.  SYNTHESIS AND REACTIONS OF NEW HIGHLY STRAINED UNSATURATED PROPELLANES, [4.2.1]PROPELLA-2,4,7-TRIENES , 1978 .