Properties of amorphous AlCuY alloy metallizations

Author

Berger, L. ; Mrosk, J.W. ; Ettl, C. ; Fecht, H.J. ; Flege, S. ; Hahn, H. ; Wolff, U.

Author_Institution

Div. of Mater., Ulm Univ., Germany

Volume

1

fYear

1999

fDate

6/21/1905 12:00:00 AM

Firstpage

46

Abstract

Amorphous metal alloys are ideally suited for interconnects in micro-electromechanical systems (MEMS) because of their resistance against migration and diffusion, and their stability in chemically aggressive environments, which should both lead to a substantial improvement of lifetime and reliability of robust sensors. Amorphous aluminium alloy metallizations are especially promising for surface acoustic wave (SAW) sensors, where the interconnects are exposed to considerable mechanical strains. In this work, first experimental results for amorphous 400 nm Al₈₄Cu₄Y₁₂ alloy thin films deposited on single crystal LiTaO₃ piezoelectric substrates at room temperature (R.T.) by ultra-high vacuum (UHV) electron beam evaporation will be presented. The composition of the films was validated by Rutherford backscattering (RBS) spectroscopy, and their amorphous structure was confirmed by X-ray diffraction (XRD) analysis. The roughness and hardness of the metallization, both important parameters for wire bonding, were investigated by scanning probe microscopy (SPM) and depth-sensing nanoindentation. The electrical resistivity was determined by four-point probe measurements. The amorphous films were annealed in UHV, and their crystallization temperature T_x was investigated by XRD

Keywords

aluminium alloys; amorphous state; copper alloys; electron beam deposition; metallic thin films; metallisation; yttrium alloys; Al₈₄Cu₄Y₁₂; LiTaO₃; Rutherford backscattering spectroscopy; X-ray diffraction; amorphous metal alloy thin film; annealing; crystallization temperature; electrical resistivity; hardness; interconnect; mechanical strain; metallization; microelectromechanical system; nanoindentation; room temperature deposition; roughness; scanning probe microscopy; single crystal piezoelectric substrate; surface acoustic wave sensor; ultra-high vacuum electron beam evaporation; wire bonding; Acoustic sensors; Aluminum alloys; Amorphous materials; Chemical sensors; Mechanical sensors; Metallization; Piezoelectric films; Robust stability; Surface acoustic waves; Temperature;

fLanguage

English

Publisher

ieee

Conference_Titel

Industrial Electronics Society, 1999. IECON '99 Proceedings. The 25th Annual Conference of the IEEE

Conference_Location

San Jose, CA

Print_ISBN

0-7803-5735-3

Type

conf

DOI

10.1109/IECON.1999.822169

Filename

822169