Copper interconnection schemes: elimination of the need of diffusion barrier/adhesion promoter by the use of corrosion-resistant low-resistivity-doped copper

Author(s):  
Shyam P. Murarka ◽  
J. M. Neirynck ◽  
William A. Lanford ◽  
W. Wang ◽  
Pei-jun Ding
1990 ◽  
Vol 203 ◽  
Author(s):  
B. Arcot ◽  
Y.T. Shy ◽  
S.P. Murarka ◽  
C. Shepard ◽  
W.A. Lanford

ABSTRACTCopper with its high conductivity, specific heat and melting point (compared to Al), is being investigated as the interconnection metal for applications both on and off the chip. Such interconnection wirings will be seperated by the dielectric layers which could be either polymers or inorganic oxides like SiO2. In such applications an adhesion promoter, which may also work as a diffusion barrier, maybe used between the dielectric and the metal film. An investigation of the diffusion and interaction of Copper with such dielectrics and insulators has been carried out in the temperature range of 200 – 500 ºC. Specifically, interactions of Copper with SiO2'P—glass, Polyimidesiloxane and Magnesium are investigated. Results of these studies will be presented and discussed.


1998 ◽  
Vol 514 ◽  
Author(s):  
Pei-I Wang ◽  
S. P. Murarka ◽  
S. Bedell ◽  
W. A. Lanford

ABSTRACTPreparation of Cu-0.3 at.% Al alloy films by homogenization anneals of metallic bilayers consisting of Cu/Cu-AI on SiO2 is studied to produce advanced copper based metallization for future ICs. The bilayer films were annealed at temperature in the range of 200°C- 400°C and the depth profiles were obtained using Rutherford Backscattering technique. It is found that Al diffuses through the undoped copper layer to surface - leading to lower Al concentration in the original Al doped Cu layer and apparently increased concentration of Al in undoped Cu (not detectable by RBS). The resistivity of these annealed films ranged from 2.1 to 2.4 μΩ-cm depending on final Al concentration achieved. Electrical stability of such MOS capacitors was also investigated. All these results will be presented and discussed showing that Al-doped copper layers can be used as diffusion barrier/adhesion promoter between the oxide ILD and copper metal.


2006 ◽  
Vol 45 (1A) ◽  
pp. 215-220 ◽  
Author(s):  
Ken-ichi Yoshimoto ◽  
Fumihiro Kaiya ◽  
Satoko Shinkai ◽  
Katsutaka Sasaki ◽  
Hideto Yanagisawa

2005 ◽  
Vol 81 (7) ◽  
pp. 1337-1343 ◽  
Author(s):  
D.G. Gromov ◽  
A.I. Mochalov ◽  
A.G. Klimovitskiy ◽  
A.D. Sulimin ◽  
E.N. Redichev

MRS Bulletin ◽  
1994 ◽  
Vol 19 (8) ◽  
pp. 23-29 ◽  
Author(s):  
J.M.E. Harper ◽  
E.G. Colgan ◽  
C-K. Hu ◽  
P. Hummel ◽  
L.P. Buchwalter ◽  
...  

Significant progress has been made in building multilevel copper interconnection systems for advanced microelectronics. In this article, we examine some of the materials science issues underlying this progress, and indicate where significant materials challenges remain. It is probable that several approaches to process integration will be developed for copper interconnections, as has been the case with aluminum systems. The first successful demonstration of a fully integrated 4-level copper/polyimide (Cu/PI) interconnection system has been described by Luther et al. of IBM. A schematic cross section of this interconnection system is shown in Figure 1, indicating multiple layers of BPDA-PDA polyimide (PI 5810), Cu lines and studs, and layers of Ta and Si3N4 which serve as diffusion barriers, adhesion layers, and stopping layers in the patterning and planarization processes. This system demonstrates excellent planarity, as shown in the SEM cross section in Figure 2. The electromigration lifetime of this Cu/PI system is greatly improved relative to state-of-the-art aluminum-based systems, and the dielectric integrity appears adequate. Signal propagation studies also confirm the performance improvements anticipated for copper as a low-resistivity conductor and the use of Cu may allow significant capacitance reduction (≃ 25%) simply by scaling Cu lines to equal the resistance of Al lines. In parallel with efforts to introduce Cu metallization for its low resistivity, extensive efforts are under way to replace SiO2 with lower dielectric constant insulators.


1998 ◽  
Vol 514 ◽  
Author(s):  
Alain E. Kaloyeros ◽  
Jean Kelsey ◽  
Cindy Goldberg ◽  
Dalaver Anjum ◽  
Xiaomeng Chen ◽  
...  

ABSTRACTThe identification of viable diffusion barrier/adhesion promoter material and associated deposition processes is a critical factor in the successful development of structurally and electrically reliable copper based metallization schemes. As feature sizes continue shrinking, such materials are expected to delivery enhanced performance at increasingly thinner layers to allow maximum space utilization by the actual conductor. In this respect, Ta and W based binary and ternary nitrides present promising solutions in view of their hardness, chemical inertness, and thermal stability to high temperatures. Additionally, their availability in amorphous form provides the added benefit of inherent absence of grain boundaries, which usually serve as a primary diffusion path. This paper presents finds from the development of low0temperature (,350°C) CVD processes for the growth of ultrathin Ta, W, Ta-Si, and WSinitride layers for sub−0.18 micron device structures. These processes employ novel inorganic and metal-organic source precursors which allow for the in-situ, one-step, growth of binary and ternary nitrides from appropriate mixtures of the corresponding source precursors. Results will also be discussed from diffusion barrier studies which established performance metris for the applicability of such materials in copper interconnect technologies.


1993 ◽  
Vol 318 ◽  
Author(s):  
Eric Kirchner ◽  
S.P. Murarka ◽  
E. Eisenbraun ◽  
A. Kaloyeros

ABSTRACTIn a copper-SiO2 dielectric multilevel interconnection scheme a diffusion barrier is needed between the metal and the dielectric to prevent the diffusion of Cu into SiO2 when subjected to thermal treatments and high electric bias. Ultra thin layers (50–100Å) of Al and Ti are being investigated for use as the required diffusion barrier as well as an adhesion promoter between Cu and SiO2 The results of our investigations, using C-V, resistance, and XPS measurements, will be presented and discussed. It will be shown that both Al and Ti reduce the SiO2 surface leading to a metal, oxygen, and Si bonded layer which acts as diffusion barrier under applied electrical bias of 1.5 MV/cm at temperatures as high as 250–300°C. Upper layers of Al and Ti are consumed by reaction with Cu. Such reactions increase the electrical resistivity and corrosion resistance of Cu (especially with Al). The results and the applicability of such barriers in practical cases will be presented and discussed.


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