Intrinsic stress-induced self-assembly of multilayer thin films for fabrication of three-dimensional micro devices

Bajwa, Rayan (2018) Intrinsic stress-induced self-assembly of multilayer thin films for fabrication of three-dimensional micro devices. [Thesis]

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This work reports on the process technology development for fabrication of three-dimensional (3D), on-chip micro devices based on self-assembly using intrinsic stresses otherwise referred to as residual or internal stresses in thin films. Stress-induced bending in different cantilever designs were modelled at various film thicknesses using finite element analysis (FEA) method and bending conditions were optimized. Intrinsic stress-induced bending mechanism is verified by fabrication of bi-layer metallic micro cantilever structures with varying stress conditions which reach bending angles of up to 137° and possibly more upon release. By modulating the loading mode (tensile or compressive) along the beam length, complex out-of-plane wavy cantilevers with multiple upward and/or downward bends were realized. The fabrication and modelling results display large overlap which further demonstrates the applicability of intrinsic stress-induced bending as a controllable technology towards fabrication of out-of-plane 3D micro components. Additionally, as a potential application to RF-MEMS inductors, stress-induced self-assembly of thin films into single and multiple-turn vertical inductors with ring and spiral geometry was investigated, and performance improvement was verified using coupled multi-physics simulation tools. Structures after transverse bending display higher Q factor and self-resonance frequency (fSR) as compared to inductor configurations in planar geometry with the same turn-density. Simulation results indicate that, performance increase of approximately 100% in both Q factor and resonance frequency can be achieved for ring and spiral inductors.
Item Type: Thesis
Uncontrolled Keywords: Intrinsic stress. -- Metal thin-film. -- Residual stress. -- Internal stress. -- Self-assembly. -- Bending. -- RF-MEMS. -- Inductor. -- Q factor. -- Roll-up. -- Micro cantilever. -- Fixed-free beam. -- İç stres. -- Metal ince film. -- Artık stres. -- İç stres. -- Kendinden montaj. -- Bükme. -- RF-MEMS. -- İndüktör. -- Q faktörü. -- Roll-up (sarmak, yuvarlamak). -- Mikro konsol. -- Sabit kiriş.
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800-8360 Electronics
Divisions: Faculty of Engineering and Natural Sciences > Academic programs > Electronics
Faculty of Engineering and Natural Sciences
Depositing User: IC-Cataloging
Date Deposited: 14 Feb 2019 09:14
Last Modified: 26 Apr 2022 10:29

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