Characterisation of residual stress in dielectric films studied by automated wafer mapping

Author

Walker, Richard ; Sirotkin, E. ; Schiavone, Giuseppe ; Terry, J.G. ; Smith, Samuel ; Mount, A.R. ; Desmulliez, Marc Philippe Y. ; Walton, A.J.

Author_Institution

Scottish Microelectron. Centre, Univ. of Edinburgh, Edinburgh, UK

fYear

2014

fDate

24-27 March 2014

Firstpage

98

Lastpage

103

Abstract

SU-8 is a negative epoxy based photoresist, which is widely used as a structural and dielectric layer in the fabrication of MEMS devices. However this material normally develops high levels of stress during processing. This paper reports detailed quantitative data following previous work, where Parylene-C has been proposed as a possible replacement for SU-8. In particular, this paper details the characterisation of residual stress in (i) SU-8 films as a function of processing temperatures and (ii) post-processing thermal treatment of Parylene-C. This characterisation includes wafer mapping strain using rotating pointer arm test structures, and deriving the stress from independent measurements of strain and Young´s modulus.

Keywords

Young´s modulus; dielectric thin films; internal stresses; micromechanical devices; photoresists; strain measurement; MEMS devices; SU-8 films; SU-8 negative epoxy; Young´s modulus; automated wafer mapping; dielectric films; dielectric layer; parylene-C; photoresist; post-processing thermal treatment; processing temperatures; residual stress; rotating pointer arm test structures; strain measurements; structural layer; wafer mapping strain; Annealing; Films; Residual stresses; Strain; Strain measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Microelectronic Test Structures (ICMTS), 2014 International Conference on

Conference_Location

Udine

ISSN

1071-9032

Print_ISBN

978-1-4799-2193-5

Type

conf

DOI

10.1109/ICMTS.2014.6841475

Filename

6841475