Sanna Yliniemi, Wei-Min Li, Tero Pilvi, Timo Malinen, Marko Pudas
Transcription
Sanna Yliniemi, Wei-Min Li, Tero Pilvi, Timo Malinen, Marko Pudas
Sanna Yliniemi, Wei-Min Li, Tero Pilvi, Timo Malinen, Marko Pudas, Juhana Kostamo Picosun Oy, Tietotie 3, FI-02150 Espoo, Finland www.picosun.com, [email protected] Atomic Layer Deposition (ALD) in MEMS Applications Top: Highly uniform and conformal TiN on a Si device wafer, deposited in a PICOSUN™ R-200 ALD reactor. SEM-micrographs, clockwise from top left: Ultra-high-k dielectric SrTiO3 film on Si trench wafer (picture credit Prof. M. Ritala, Univ. of Helsinki) and ~100 % conformal ZnO:Al in a deep trench of AR 60:1 (pictures by VTT Technical Research Centre of Finland). • Conformal, electrically insulating layers deposited at low temperatures • Etch masks, etch stop layers • Conductive seed layers for plating purposes • Conformal, thermally conductive layers • Hydrophobic layers to reduce stiction • Hermetically sealed coatings • Biocompatible coatings • Closing of nanoscale pores • Optical layers (reflective, antireflective, black absorbers) • Layers reducing frictional wear • Charge dissipative layers • Diffusion barrier, adhesion and seed layers in through-silicon vias On the left: High-Q mechanical silicon oscillator (O. Hahtela et. al., J. Micromech. Microeng. 17 (2007) 737). On the right: ALD-enabled MEMS microengine (T. M. Mayer et. al., Appl. Phys. Lett. 82 (2003) 2883). On the left: MEMS actuator. On the right: Large force electrostatic MEMS comb drive. ALD Al2O3 and ZnO proposed for use as charge dissipative layers (C. F. Herrnlann et. al., Sens. Actuators A: Phys. 135 (2007) 262). On the left: 3D micromechanical compass (Kyynäräinen et. al., Sensor Letters 5 (2007) 1). On the right: ALD-enabled fluorine dry etch barrier (trenches in Si etched in the ICP after patterning Al2O3 by lift-off with 2 µm resist mask). Pictures by VTT Technical Research Centre of Finland. PICOSUN – Pioneers of ALD • ALD: Chemical vapor based coating method of ultra-thin, 100 % uniform, conformal, crack-, defect- and pinhole-free thin films of high chemical and structural purity • Film formation based on self-limiting, self-controlled gas-solid chemical adsorption reactions on the surface • Depositable materials range from basic oxides, nitrides, sulphides, fluorides to pure metals (incl. noble ones), polymers, graded/mixed/doped layers and nanolaminates with possibility to tailor the layers’ properties on molecular level • Possible to coat not only Si wafers but 3D objects, throughporous and powderous samples • PICOSUN has pioneering experience in the field of ALD since the invention of the technology in the early ´70’s • PICOSUN develops and manufactures state-of-the-art ALD systems with unparalleled knowhow, vision and expertise in the field • Today, PICOSUN™ ALD systems are in daily use in frontline industries and research organizations on four continents The work has been performed in EPAMO (ref. 270692-2) project, which is funded by public authorities of participant countries as well as by the ENIAC Joint Undertaking.