Two-Photon Polymerization Used to Fabricate Electrothermal MEMS Actuators and Rotational Parts

This thesis describes the design, fabrication process, and testing of complex and dynamic electrothermal Micro-Electro-Mechanical Systems (MEMS) using two-photon polymerization (2PP). Typical MEMS processes can take considerable time to design and fabricate while the design, fabrication, and testing using 2PP can cut the time down to a single day. This short time frame makes the use of 2PP appealing for quick design changes and prototyping. Using computer-aided-design software, dynamic MEMS actuators and gear systems were realized using 2PP. 2PP is a precise, additive manufacturing process where two photons are simultaneously absorbed by a photoresist, hardening the polymer, to build complicated, three-dimensional (3D) structures. Once these structures are produced, they are sputter coated with aluminum to create an electrically conductive and isolated surface that can be used to heat the photoresist using electrical current. This process allows MEMS devices to have structures they had not been achievable using conventional bulk and surface micromachining processes. Leveraging these structures and photoresist characteristics, an electrothermal actuator, in the shape of a chevron, as well as gears were manufactured. Optical imaging was used to characterize the deflection and disfiguration of the chevron arms. The results showed that the chevrons demonstrated greater deflection than conventionally made chevron actuators. In addition, the arm disfiguration is analogous to surface micromachined polycrystalline silicon chevrons allowing for conventional actuation models to be valid. Microscale gears, using tight design parameters, stay on-axis while maintaining precise teeth meshing for a drive pawl to grab. The combination of the chevron and gear produced a functional rotational drive that converts linear motion into rotational motion.