A microstructure for in situ determination of residual strain

Author

Pan, Chi Shiang ; Hsu, Wensyang

Author_Institution

Dept. of Mech. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan

Volume

8

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

200

Lastpage

207

Abstract

This work presents a new strain sensor with a compact structure. The strain sensor comprises of a pair of cantilever beams with different lengths connected by a short tip. The residual strain causes two beams to deflect each other, thereby magnifying the deflection, which is measured by the tip. The displacement is independent of both Young´s modulus and the film´s thickness. An analytical model is derived to relate the measured displacement to residual strain. Finite-element modeling is also used to analyze the model. This work also thoroughly considers other factors that influence the designs and the implicit limitations of the strain sensors. Experimental results with an SiO₂ film as well as undoped LPCVD polysilicon films are used to demonstrate the effectiveness of the proposed structure

Keywords

finite element analysis; microsensors; strain sensors; thin films; LPCVD polysilicon film; Si; SiO₂; SiO₂ film; analytical model; cantilever beam; finite element model; in situ measurement; microstructure; residual strain; strain sensor; Analytical models; Capacitive sensors; Displacement measurement; Microstructure; Residual stresses; Sensor phenomena and characterization; Strain measurement; Stress measurement; Structural beams; Testing;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/84.767116

Filename

767116