2 results for Aw, KC

  • Analysis of HSG-7000 Silsesquioxane-based Low-K Dielectric Hot Plate Curing Using Raman Spectroscopy

    Doux, C; Aw, KC; Nieuwoudt, MK; Gao, Wei (2006)

    Journal article
    The University of Auckland Library

    HSG-7000 by Hitachi Chemicals Ltd., is a spin-on low-k dielectric offering a dielectric constant of approximately 2.2. It is a silsesquioxane based low-k dielectric with an empirical formula of [CH3–SiO3/2]n. The standard thermal curing for HSG 7000 is at least 30 min at 400 °C with N2 ambient. This paper aims to demonstrate that curing using a low-cost hot plate in atmospheric ambient is possible. The chemical bonding structure will be studied using Raman spectroscopy. The ratios of the areas of the Si–O–Si /Si–CH3 of the Raman bands were used to determine the structure of the different hot plate curing temperatures and time. Results showed that hot plate curing at 425° for 15 min will yield a ratio closest to those cured with the standard furnace process which is predominantly ladder structure. The results also show that the dielectric constant remains essentially constant with different hot plate curing temperatures and time.

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  • Control of IPMC actuators for micro-fluidics with adaptive 'online' Iterative feedback tuning (IFT)

    McDaid, AJ; Aw, KC; Haemmerle, Enrico; Xie, SQ (2011-04-29)

    Journal article
    The University of Auckland Library

    Ionic polymer metal composites (IPMCs) are actuators that lend themselves well to microfluidic applications due to their lightweight, flexibility, ability to tailor their geometry, as well as the capability to be miniaturized and implanted into microelectro-mechanical systems devices. The major issue with implementing IPMCs into such devices is the ability to control their actuation and, hence, their reliability over a long period of time. This paper presents a novel iterative feedback tuning (IFT) algorithm that tunes the system online using experimental data during normal system operation. The controller adaptively tunes the highly nonlinear and time varying IPMC for a newly proposed micropump. This demonstrates the ability of the system to have a reliable performance over a long period of time without the need of any offline tuning or system identification. The system was run for 20 controller updates. This corresponds to 10 and 20 min of operation for the 0.1 and 0.05 Hz reference inputs, respectively. 100 and 300 $mu$m amplitudes were tested to demonstrate the ability of the system to adaptively tune to different input signals. Experimental results show the newly proposed IFT algorithm has successfully tuned the controller to achieve up to 92% better performance when compared with a conventional model-based tuned controller.

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