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Proceedings Paper

Laser-assisted wet chemical etching of metals for microfabrication
Author(s): Rainer Nowak; Simeon Metev; Gerd Sepold
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Paper Abstract

Laser-induced wet chemical etching of Co, Cr, Cu and Ti in aqueous solutions of potassium hydroxide and phosphoric acid was investigated using an Ar-laser operating at 514 nm. Etching of thin metal films on glass substrates and metal foils was obtained at static etch rates up to about 10 micrometers /s at an incident laser power of about 1 W. Measured background etch rates were less than 10-5 nm/s. EDX-analysis of Ti foils etched in phosphoric acid revealed no enrichment of phosphorous near the laser interaction zone. An observed exponential dependence of static etch rates on laser power is interpreted in terms of dominating thermally activated chemical reactions at the metal surface. Laser direct writing of thin transparent lines in metal films on glass was obtained at writing velocities of about 1 mm/s and a laser power of about 0.3 W. Smallest line widths of about 3 micrometers were obtained which are about a factor of two smaller than the laser focal spot diameter. This observation is in agreement with dominating thermally activated surface reactions. Cutting of thin Ti foils (25 micrometers ) was obtained by laser chemical etching at a velocity of about 30 micrometers /s and an incident laser power of about 0.8 W. Wall angles between 70 and 80 degree(s) were found to depend on experimental parameters.

Paper Details

Date Published: 7 September 1994
PDF: 10 pages
Proc. SPIE 2207, Laser Materials Processing: Industrial and Microelectronics Applications, (7 September 1994); doi: 10.1117/12.184772
Show Author Affiliations
Rainer Nowak, Bremer Institut fuer Angewandte Strahltechnik (Germany)
Simeon Metev, Bremer Institut fuer Angewandte Strahltechnik (Germany)
Gerd Sepold, Bremer Institut fuer Angewandte Strahltechnik (Germany)


Published in SPIE Proceedings Vol. 2207:
Laser Materials Processing: Industrial and Microelectronics Applications
Eckhard Beyer; Maichi Cantello; Aldo V. La Rocca; Lucien Diego Laude; Flemming O. Olsen; Gerd Sepold, Editor(s)

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