Contents - Akademi Sains Malaysia

ASM Science Journal, Volume 7(1), 2013— bottom conductor, via, and top conductor. The chosenmaterial for the coils was Cu, because of its excellentconductivity.Illustrations of the three-dimensional coil structureare shown in Figure 1. The layer structure from bottomupwards, starts with a substrate of alumina ceramic orglass. This is followed by a metal layer comprising of abottom conductor. Next, is the insulation layer used toinsulate between the bottom and top metal layers. Thethree-dimensional structure is then completed with the topmetal layer which made up of the top conductor. The topand bottom conductors are connected by means of vias.SIMULATIONInvestigations on the physical characteristic of the coilswere executed by using FEM simulation software. Theaim of the simulation was to measure the inductance andmagnetic flux density of the coils to manipulate threephysical characteristics of the coil i.e. width of the coil;distance between successive coils; and the gap between thetop and bottom coils.First, we modelled the geometry of three-dimensionalcoil by using draw function. The initial dimension of thecoils' width, distance between successive coils, and gapbetween the top and bottom coils were 20 µm, 50 µm and40 µm, respectively.The thickness of the coils were set at 20 µm and thenumber of windings were 2. Windings were kept at aminimum to simplify the modeling geometry, modelmeshing and solving processes. The current passingthrough the coils was set at 1A for all conditions.Figure 2 illustrates the model and defines the threephysical characteristics of the coil to be manipulated bymeans of simulation.After geometry modeling, the next step was to set themodule and application mode for simulation process. Sincethe aim of the simulation was to determine the inductanceand magnetic flux density at constant current, the moduleand application mode chosen were AC/DC module andmagnetostatics.Mesh process was done after the model Physics settingsin which the subdomain and boundary of the model hadbeen set. Consecutively, the solving process was executedafter the meshing. Table 1 summarizes the simulationprocesses in this work.As a preliminary study, this model did not include themagnetic core. This is to simplify the simulation processTop conductorInsulating layerBottom conductoron substrateFigure 1. Three-dimensional coils structure.28