Thermal stability of tungsten-titanium diffusion barriers for silver metallization

被引：24
作者：
Bhagat, S. K. [1 ]
Theodore, N. D. [1 ,2 ]
Alford, T. L. [1 ]
机构：
[1] Arizona State Univ, Sch Mat, Tempe, AZ 85287 USA
[2] Freescale Semicond Inc, Wireless & Packaging Syst Lab, Tempe, AZ USA
来源：
THIN SOLID FILMS | 2008年 / 516卷 / 21期
基金：
美国国家科学基金会;
关键词：
silver metallization; diffusion barrier layers; tungsten; titanium;
D O I：
10.1016/j.tsf.2008.03.021
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
Tungsten-titanium thin films have been extensively applied as barrier layers for aluminum and copper metallization. The present work investigated the feasibility of tungsten-titanium barrier layers for silver metallization. Reactive sputtered W-Ti was deposited on a Si wafer followed by an Ag thin film on top. The resulting samples were annealed in vacuum at temperatures up to 700 degrees C. These were then characterized using X-ray diffractometry, Rutherford backscattering spectrometry, secondary ion mass spectroscopy, transmission electron microscopy, scanning electron microscopy and four point probe analysis. The analyses showed that the samples were stable up to 600 degrees C. Secondary ion mass spectroscopy showed that above 600 degrees C, agglomeration of silver film started. Si started moving into the tungsten-titanium film above 600 degrees C. Movement of Si resulted in local Si voiding as indicated by transmission electron microscopy. At Si/W-Ti interface, silicide formation occurred. Silver agglomerated completely at 700 degrees C. These results showed that W-Ti was an effective barrier layer for silver metallization for process temperatures below 600 degrees C. (C) 2008 Elsevier B.V. All rights reserved.
引用
收藏
页码：7451 / 7457
页数：7
相关论文
共 29 条
[1]   PASSIVATION OF CU VIA REFRACTORY-METAL NITRIDATION IN AN AMMONIA AMBIENT [J].
ADAMS, D ;
ALFORD, TL ;
THEODORE, ND ;
RUSSELL, SW ;
SPREITZER, RL ;
MAYER, JW .
THIN SOLID FILMS, 1995, 262 (1-2) :199-208
[2]   Encapsulation of Ag films on SiO2 by Ti reactions using Ag-Ti alloy/bilayer structures and an NH3 ambient [J].
Alford, TL ;
Adams, D ;
Laursen, T ;
Ullrich, BM .
APPLIED PHYSICS LETTERS, 1996, 68 (23) :3251-3253
[3]   Stability of silver thin films on various underlying layers at elevated temperatures [J].
Alford, TL ;
Chen, LH ;
Gadre, KS .
THIN SOLID FILMS, 2003, 429 (1-2) :248-254
[4]   TITANIUM-TUNGSTEN CONTACTS TO SILICON .2. STABILITY AGAINST ALUMINUM PENETRATION [J].
BABCOCK, SE ;
TU, KN .
JOURNAL OF APPLIED PHYSICS, 1986, 59 (05) :1599-1605
[5]   Al/TixW1-x metal/diffusion-barrier bilayers: Interfacial reaction pathways and kinetics during annealing [J].
Bergstrom, DB ;
Petrov, I ;
Greene, JE .
JOURNAL OF APPLIED PHYSICS, 1997, 82 (05) :2312-2322
[6]   Tungsten-titanium diffusion barriers for silver metallization [J].
Bhagat, Shekhar ;
Han, Hauk ;
Alford, T. L. .
THIN SOLID FILMS, 2006, 515 (04) :1998-2002
[7]   STRUCTURAL CHARACTERIZATION AND THERMAL-STABILITY OF W/SI MULTILAYERS [J].
BRUNEL, M ;
ENZO, S ;
JERGEL, M ;
LUBY, S ;
MAJKOVA, E .
JOURNAL OF MATERIALS RESEARCH, 1993, 8 (10) :2600-2607
[8]   Silver diffusion and defect formation in Si (111) substrate at elevated temperatures [J].
Chen, LH ;
Zeng, YX ;
Nyugen, P ;
Alford, TL .
MATERIALS CHEMISTRY AND PHYSICS, 2002, 76 (03) :224-227
[9]   DIRECT W-TI CONTACTS TO SILICON [J].
COHEN, SS ;
KIM, MJ ;
GOROWITZ, B ;
SAIA, R ;
MCNELLY, TF ;
TODD, G .
APPLIED PHYSICS LETTERS, 1984, 45 (04) :414-416
[10]   Performance of vertical power devices with contact-level copper metallization [J].
Cook, J ;
Azam, M ;
Leung, P ;
Grupen, M .
THIN SOLID FILMS, 1999, 348 (1-2) :14-21
123