AVS 59th Annual International Symposium and Exhibition
    Thin Film Monday Sessions
       Session TF-MoM

Paper TF-MoM4
Quasi-ALD for Deposition of a Water Resistive Barrier Layer and Prevent Electronic Devices from Water Shock

Monday, October 29, 2012, 9:20 am, Room 11

Session: ALD Enabled Applications
Presenter: V. Gupta, Brigham Young University
Authors: V. Gupta, Brigham Young University
M.R. Linford, Brigham Young University
Correspondent: Click to Email
Water resistant surfaces and devices have an ever increasing importance in various areas of technology, including electronics (e.g., cell phones), fabrics, shoes, chemical handling equipment, and hearing aids to name only a few. However, while important and effective against splashes, ultrathin hydrophobic films are not always sufficient for water proofing devices. Herein we describe the development of a water resistant barrier layer, deposited by a method similar to atomic layer deposition, which can also be made hydrophobic by deposition of fluorosilanes, for imparting improved protection against water to underlying surfaces and devices. The resulting barrier has been found effective in resisting the infiltration of water and preventing underlying surfaces such as electronic circuits from water shock. The precursors we use appear to have low toxicity in their molecular and (especially) deposited form, are inexpensive, have good vapor pressures so they can be deposited at low temperature, and can be deposited in a straightforward manner because of their high reactivity. Different plasma pre-treatments of substrates have been studied, although good uniformity in the deposition takes place on substrates, such as Si/SiO2 and nylon, that have not been primed in any way. Film growth on Si/SiO2 and nylon spin coated onto Si/SiO2 has been monitored by spectroscopic ellipsometery, which shows consistent increases in film thickness with deposition cycles, contact angle goniometery, which shows similar wetting properties for all layers of the films and is consistent with deposition of a constant surface chemistry, XPS, which shows the expected elements in the film, AFM, which provides surface roughness, and ToF-SIMS, which is also a probe of the surface chemistry.This barrier layer has been tested on model circuit boards and results are consistent with both the number of layers deposited and their mode of deposition. That is, water damage shows a proportional decrease with an increase in the number of the above mentioned layers. This process appears to be applicable on multiple substrates ranging from inorganic to organic surfaces. Presently we are working on increasing the number of layers and more effective crosslinking of the films. Additional film characterization will also be done by RBS and NRA.