Organ-on-chip (OOC) devices are micro-engineered three-dimensional (3D) biomimetic systems that can be used to create in vitro models of human tissue. They provide an alternative for conventional cell culture tools in pharmaceutical R&D. Moreover, these devices can contribute in research focused on understanding complex disease processes. OOC often includes porous membranes made of polydimethylsiloxane. The conventional method to create these membranes has drawbacks such as a limited achievable porosity. A novel approach to create porous PDMS membranes is to use micro-electro-mechanical systems (MEMS)-based fabrication technologies such as etching. With this method, the porosity of the membranes can be finely tuned. Quirós-solano et al.1 used this method and created a thin (>10 m) highly porous membrane and 3D scaffolds. Furthermore, their membrane could be easily transferred from its substrate to an OOC. In order to achieve this transfer, they incorporated a sacrificial layer of poly acrylic acid (PAA). The high porosity of the scaffold was created by introducing lateral gaps between the vertical pores of the scaffold. The dimensions of the gaps can be tuned by changing the etching time. However, this resulted in complete etching of the underlying layer. In order to reduce the etching time, this project is focused on the mechanism that created the lateral gaps. The contribution of bias power, chamber pressure and chuck temperature to that mechanism are investigated. With the knowledge gained from these experiments, the dimensions of the gaps were tuned by changing the aforementioned parameters.Furthermore, in this work the fabrication process of Quirós-Solano et al. is adapted to create thick (>20 m) PDMS membranes. These membranes were successfully fabricated and employed by researchers at the University of Technology in Eindhoven.