Mechanical characterization of post-buckled micro-bridge beams by micro-tensile testing

• Published in: Microsystem technologies : sensors, actuators, systems integration actuators, systems integration, 2010-03, Vol.16 (3), p.375-380
• Main Authors: Zhang, Duanqin, Chu, Jinkui
• Format: Article
• Language: English
• Subjects: Accuracy; Applied sciences; Bridge loads; Deformation; Electronics; Electronics and Microelectronics; Engineering; Ethanol; Exact sciences and technology; Fracture strength; Grooves; Instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical Engineering; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Mechanical properties; Methods; Microelectromechanical systems; Microelectronic fabrication (materials and surfaces technology); Micromachining; Micromechanical devices and systems; Modulus of elasticity; Nanotechnology; Physics; Postbuckling; Precision engineering, watch making; Residual stress; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors; Silicon dioxide; Silicon wafers; Stiffness coefficients; Technical Paper; Tensile tests; Thin films
• ISSN: 0946-7076; 1432-1858
• DOI: 10.1007/s00542-009-0934-y

A micro-tensile testing system has been developed to measure the mechanical properties of post-buckled silicon dioxide micro-bridge beams. A kind of vernier-groove carrier is presented to improve alignment precision and repeatability of the measurement, and the stiffness coefficient of the tensile system is calibrated in situ in order to obtain the deformation of the tensile beams. Through analyzing a series of stress states in the beam over film preparation, post-buckling and unfolding of the beam, the initial residual stress in the film is obtained from the original load–displacement curves. The residual stress of 354 MPa is consistent with that calculated from the theory of finite deflection of buckled beams. Young’s modulus and tensile fracture strength are also obtained from the load–displacement curves. The measured modulus and strength are 64.6 ± 3 GPa and 332–489 MPa respectively. The measured properties of the thermal silicon dioxide film are reasonably coherent with other reports.