Scheduled System Maintenance on May 29th, 2015:
IEEE Xplore will be upgraded between 11:00 AM and 10:00 PM EDT. During this time there may be intermittent impact on performance. We apologize for any inconvenience.
By Topic

Fabrication of Very-High-Aspect-Ratio Micro Metal Posts and Gratings by Photoelectrochemical Etching and Electroplating

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)
Guangyi Sun ; Mech. & Aerosp. Eng. Dept., Univ. of California at Los Angeles (UCLA), Los Angeles, CA, USA ; Hur, J.I. ; Xin Zhao ; Kim, J.Y.

A high-yield fabrication process for dense arrays of very-high-aspect-ratio (VHAR) freestanding metal posts and gratings is developed. Silicon molds of regularly arranged through-holes or trenches are first fabricated by photoelectrochemical etching. By studying the etching parameters, including geometry constraint, current density and potential, electrolyte concentration, and etching time, we succeed to produce dense arrays of VHAR holes ( depth = 610 μm; diameter = 5 μm; pitch = 14 μm) and trenches (depth = 320 μm ; width = 4 μm; pitch = 8 μm) with yields higher than 99% on 2-cm2 processing areas. The VHAR molds are then filled with metals using a new bottom-up electroplating technique, which features an intermittent vacuum degassing to remove the air and hydrogen bubbles from such deep and narrow voids during the plating. Zinc and nickel are successfully electroplated in high quality, and the freestanding metal structures are obtained by removing the silicon molds by XeF2 etching. Obtained are maximum aspect ratios of 120 : 1 for posts (height = 600 μm; diameter = 5 μm; pitch = 14 μm) and over 60 : 1 for gratings (height = 250 μm; width = 4 μm; pitch = 8 μm) with yields higher than 99% on ~ 0.5-1-cm2 samples.

Published in:

Microelectromechanical Systems, Journal of  (Volume:20 ,  Issue: 4 )