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Title: The Role of Interfacial Properties on MEMS Performance and Reliability

Abstract

We have constructed a humidity-controlled chamber in which deflections of polysilicon cantilever beams are observed by interferometry, resulting in in-situ adhesion measurements within a fracture mechanics framework. From adhesion energy measurements for uncoated hydrophilic beams, we demonstrate an exponential dependence of adhesion on relative humidity (RH). We can explain this trend with a single-asperity model for capillary condensation. For coated hydrophobic beams, adhesion is independent of RH up to a threshold value which depends on the coating used. However, we have found that exposure to very high RH ({ge}90%) ambients can cause a dramatic increase in adhesion, surprisingly with a stronger effect for perfluorodecyltrichlorosilane (FDTS, C{sub 10}H{sub 4}F{sub 17}SiCl{sub 3}) than octadecyltrichlorosilane (ODTS, C{sub 18}H{sub 37}SiCl{sub 3}). Newly developed computational mechanics to measure adhesion in the presence of an applied load allow us to explore how the adhesion increase develops. We believe that water adsorption at silanol sites at the FDTS/substrate interface, possibly exacerbated by coupling agent migration, leads to water islanding and the subsequent adhesion increase at very high RH levels.

Authors:
; ; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
7264
Report Number(s):
SAND99-1294C
TRN: AH200116%%304
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: EOS/SPIE Conference on Microsystems Metrology and Inspection, Munich (DE), 06/14/1999--06/18/1999; Other Information: PBD: 21 May 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; INTERFACES; MICROELECTRONIC CIRCUITS; MINIATURIZATION; ADHESION; COATINGS; FRACTURE MECHANICS; PERFORMANCE; RELIABILITY

Citation Formats

de Boer, M P, Knapp, J A, Mayer, T M, and Michalske, T A. The Role of Interfacial Properties on MEMS Performance and Reliability. United States: N. p., 1999. Web.
de Boer, M P, Knapp, J A, Mayer, T M, & Michalske, T A. The Role of Interfacial Properties on MEMS Performance and Reliability. United States.
de Boer, M P, Knapp, J A, Mayer, T M, and Michalske, T A. Fri . "The Role of Interfacial Properties on MEMS Performance and Reliability". United States. https://www.osti.gov/servlets/purl/7264.
@article{osti_7264,
title = {The Role of Interfacial Properties on MEMS Performance and Reliability},
author = {de Boer, M P and Knapp, J A and Mayer, T M and Michalske, T A},
abstractNote = {We have constructed a humidity-controlled chamber in which deflections of polysilicon cantilever beams are observed by interferometry, resulting in in-situ adhesion measurements within a fracture mechanics framework. From adhesion energy measurements for uncoated hydrophilic beams, we demonstrate an exponential dependence of adhesion on relative humidity (RH). We can explain this trend with a single-asperity model for capillary condensation. For coated hydrophobic beams, adhesion is independent of RH up to a threshold value which depends on the coating used. However, we have found that exposure to very high RH ({ge}90%) ambients can cause a dramatic increase in adhesion, surprisingly with a stronger effect for perfluorodecyltrichlorosilane (FDTS, C{sub 10}H{sub 4}F{sub 17}SiCl{sub 3}) than octadecyltrichlorosilane (ODTS, C{sub 18}H{sub 37}SiCl{sub 3}). Newly developed computational mechanics to measure adhesion in the presence of an applied load allow us to explore how the adhesion increase develops. We believe that water adsorption at silanol sites at the FDTS/substrate interface, possibly exacerbated by coupling agent migration, leads to water islanding and the subsequent adhesion increase at very high RH levels.},
doi = {},
url = {https://www.osti.gov/biblio/7264}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {5}
}

Conference:
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