A Humidity-Sensitive Capacitor Based on Fan-Out Panel Level Package Technology

A highly humidity-sensitive comb capacitor using RDL (Redistribution Layer) and moisture-sensitive polyimide (MS- PI) material is constructed based on low cost Fan-Out Panel Level Package technology. The comb capacitor is design and simulated using HFSS. The length, width and spacing of the comb capacitor are 2.5mm, 0.5mm, and 0.25mm respectively. The dielectric constant of the MS-PI material using in this design ranges from 2.96 to 3.6 as the relative humidity (RH) varies from 0% RH to 100%RH. As a result the proposed comb HS capacitor achieves capacitance ranging from 4.13pF to 4.18pF(measured at IMHz frequency) with 0.15% non-linearity. The presented HS capacitor in this paper creates a new economical method to manufacture humidity-sensitive capacitor which is the sensing component in humidity sensor.