Development of an SU-8 MEMS process with two metal electrodes using amorphous silicon as a sacrificial material

Abstract

This work presents an SU-8 surface micromachining process using amorphous silicon as a sacrificial material, which also incorporates two metal layers for electrical excitation. SU-8 is a photo-patternable polymer that is used as a structural layer for MEMS and microfluidic applications due to its mechanical properties, biocompatibility and low cost. Amorphous silicon is used as a sacrificial layer in MEMS applications because it can be deposited in large thicknesses, and can be released in a dry method using XeF 2 , which alleviates release-based stiction problems related to MEMS applications. In this work, an SU-8 MEMS process was developed using α-Si as a sacrificial layer. Two conductive metal electrodes were integrated in this process to allow out-of-plane electrostatic actuation for applications like MEMS switches and variable capacitors. In order to facilitate more flexibility for MEMS designers, the process can fabricate dimples that can be conductive or nonconductive. Additionally, this SU-8 process can fabricate SU-8 MEMS structures of a single layer of two different thicknesses. Process parameters were optimized for two sets of thicknesses: thin (5-10 μm) and thick (130 μm). The process was tested fabricating MEMS switches, capacitors and thermal actuators.

A review of piezoelectric polymers as functional materials for electromechanical transducers

“…Although ZnO has a small coupling coefficient, the significance of such a composite lies in the selection of the SU-8 polymer. SU-8 is a UV negative photopatternable polymer which has been utilized in different polymer MEMS applications [76,77]. Therefore, direct UV patterning of the spin coated composite simplifies the fabrication of MEMS devices.…”

Fabrication of a coupler waveguide cavity based on large-scale sacrificial layer technology

“…Terahertz science and technology has made rapid developments over the past two decades and now has great potential in the application of high frequency wireless communications especially in the military field [1] . Currently, with the advanced MEMS technologies [2] , microsensors [3] and microcouplers have been used in many industrial fields [4,5] .…”