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Proceedings Paper

Aluminum passivation in saturated TMAHW solutions for IC-compatible microstructures and device isolation
Author(s): Pasqualina M. Sarro; Sebastiano Brida; W. van der Vlist
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Paper Abstract

Tetramethyl ammonium hydroxide (TMAH) solutions have been used to realize IC-compatible micromachined structures and device isolation. THe very low etch rate of PECVD dielectric layers and the possibility to passivate the aluminum metalization by doping the solution with silicon, increase the range of applications of this etchant and simplify both the post processing and the etch set-up configuration. Solutions of TMAH and water with addition of solid silicon or silicic acid have been used to study the effect of solution saturation on the passivation of aluminum. The etch rate of silicon, selectivity to masking materials and quality of the etched surfaces has been evaluated in both types of doped solutions in the temperature range 70 degrees-90 degrees C. An etch rate of less than 10nm/hr for the Al/1 percent Si metal layer has been measured in the saturated solutions. Further, the use of additives, such as IPA and pyrocatechol, on the etchant characteristics has been investigated. The addition of IPA has little or no influence on the etching characteristics, while very little quantities of pyrocatechol are sufficient to cause major improvements on the etching uniformity and surface quality, with no negative effect on the aluminum passivation.

Paper Details

Date Published: 23 September 1996
PDF: 9 pages
Proc. SPIE 2879, Micromachining and Microfabrication Process Technology II, (23 September 1996); doi: 10.1117/12.251213
Show Author Affiliations
Pasqualina M. Sarro, Delft Univ. of Technology (Netherlands)
Sebastiano Brida, Univ. di Trento (Italy)
W. van der Vlist, Delft Univ. of Technology (Netherlands)


Published in SPIE Proceedings Vol. 2879:
Micromachining and Microfabrication Process Technology II
Stella W. Pang; Shih-Chia Chang, Editor(s)

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