Table 5.

Overview of various polymers with their representative fabrication process, features, and applications in MEMS

Polymer	Fabrication process	Features	Applications
Parylene	Chemical vapor deposition (CVD) Etching by oxygen plasma Hot embossing Lithography	Young’s modulus, E ~ 5 GPa Chemically inert Low intrinsic stress and gas permeability Hydrophobic Optically transparent Vulnerable to temperature	Electrostatic actuator [155] Micro-valve [165] Spring [166] Electrostatic micro-peristaltic pump [167]
Polypropylene	Injection molding Laser ablation	Young’s modulus, E ~ 1.45 GPa Vulnerable to oxidants Thermal resistance Large thermal coefficient of expansion Opaque	Surface stress cantilever sensor [156] Component in air-coupled piezoelectric transducer [168] Piezo-electret film transducer [169]
Fluoropolymer  Teflon®  Polytetrafluoroethylene  Tefzel®  Fluoroethylenepropylene	Spin coating Ion beam sputter etching Magnetically controlled reactive ion etching	Young’s modulus, E ~ 1.45 GPa (Teflon®) Chemically inert Hydrophobic Thermally stable Teflon® smoothest surface morphology	AFM-based biochemical sensor [157] Micro-tube [170] Micro-fluidic channel [171]
SU-8	Spin coating Photolithography Excimer laser patterning Pyrolysis Dry etching	Young’s modulus, E ~ 5 GPa Low molecular weight Chemically inert High refractive index Compatibility with grayscale lithography	Optical waveguide [172] Micro-needles [173] Micro-resonator [174] AFM cantilever [175]  Surface stress cantilever sensor [68]
Polyethylene terephthalate	Excimer laser patterning and laser ablation	Young’s modulus, E ~ 2.8 GPa Excellent resistance to moisture High impact resistance	Cantilever biosensor [159] Mechanical substrate [176] Micro-pump [177]
Polyimide	Spin coating Dry etching using oxygen or fluorine plasma Hot embossing Lithography	Young’s modulus, E ~ 7.5 GPa Chemically inert Stable at high temperature and heat Vulnerable to alkalis Low susceptibility to moisture	Scanning probe [160] Tactile sensor [178, 179] Humidity sensor [180] Micro-channels [181]
TOPAS®	Spin coating Nano-imprint lithography	Young’s modulus, E ~ 3.5 GPa High chemical inertness Low susceptibility to moisture Good optical transmission	Water vapor sensor [161] Optical waveguide [182] Micro-fluidic devices [183]
Polystyrene	Injection molding Solvent casting technique	Young’s modulus, E ~ 3.0 GPa Vulnerable to moisture Optically transparent	Surface stress sensor [162] Accelerometer [184]
PDMS	Spin coating Cast molding	Young’s modulus, E ~ 0.75 MPa Incompatible with organic solvents Optically transparent Gas permeable	Micro-valve [185] Magnetic actuator [186] Micro-pump [187] Micro-channel [188]
PMMA	Injection molding Hot embossing Wire printing Laser ablation	Young’s modulus, E ~ 3.1 GPa Low susceptibility to moisture Optically transparent	Micro-channel [189] Acceleration sensor [190] Nano-structure arrays [191]