RF MEMS switches fabrication by using SU-8 technology

Abstract

In this paper we present a novel process based on SU-8 technology for the fabrication of double clamped RF MEMS capacitive shunt switches in coplanar configuration. The key element of the exploited process is the MicroChem SU-8 2002 negative photoresist. The polymeric material is widely used in MEMS device processes because of its excellent thermal and chemical stability. In this paper, SU-8 polymer has been utilized in a double way to get suspended structures as double clamped beams: (i) SU-8 for the lateral supports, and (ii) as a sacrificial layer for the release of the suspended membrane. Preliminary RF tests on the manufactured switches have been done, and the measured electrical performances are in good agreement with the performed simulations

Design, simulation and analysis of a digital RF MEMS varactor using thick SU-8 polymer

“…In this process, 150 °C instead of 300 °C for plated shower is used to make sure it will not affect the SU-8 layer. Next, around 7 μm thickness of polymer or any sacrificial layer such as SU-8 or polyimide is spin coated and cured up to 200 °C to form the anchor and sacrificial layer (Lucibello et al 2013). Adhesion between the sacrificial layer material and SU-8 is needed to be taken to account.…”

“…Recently, SU-8 was used as a passivation layer to elevate co-planar waveguide (CPW) for realising a low loss transmission line using low resistivity silicon wafer (ρ < 100 Ω cm). (Lucibello et al 2013;Marcelli et al 2008) had used SU-8 as a lateral support for RF MEMS switch and sacrificial layer. Our previous work reported that by depositing and patterning 25 µm thick SU-8 layer on a silicon substrate, the parasitic capacitance due to fringing field and loss of the varactor could be reduced, hence increasing the capacitance ratio and the Q-factor of the proposed RF MEMS varactor (Ramli et al 2016a, b).…”

The Image Phase Approach for the Design of Rf Mems Shunt Switches

“…Imposing in Equation (21) the φ ihc value given by Equation (20), after some algebra, the following quadratic equation in the unknown U is obtained:…”

“…In [20] the authors have recently presented a novel process based on SU-8 for the fabrication of MEMS shunt capacitive devices. SU-8 is a negative photoresist, and has been used both for the lateral supports for the suspended membrane and as sacrificial layer.…”

“…SU-8 is a negative photoresist, and has been used both for the lateral supports for the suspended membrane and as sacrificial layer. In that paper [20] all the technological aspects concerning the fabrication of such a component have been discussed, and therefore for sake of brevity will not be presented here again. The final structure is depicted in Figure 4.…”