A rapid technique to integrate micro-components on released MEMS dies using SU-8

This technical note reports a rapid technique to post-process and assemble micro-components onto dies including released movable microstructures. The method is applied to microelectromechanical systems (MEMS) chips that were fabricated using a commercial process, PolyMUMPs from MEMSCAP. It allows the assembly of a micro-polyhedron over released micromotors and ensures that the micromotors remain fully functional. The micro-polyhedrons are fabricated using laser ablation and are spin coated with a thin layer of SU-8, acting as a bonding layer. Then, they are bonded to chips that are placed on a 3D integration platform with a navigating mask, which protects the released structure during the subsequent assembly steps. The resulting micro-polyhedron-integrated-micromotors were tested and found to rotate similarly to devices without micro-polyhedrons, demonstrating that the developed procedure can be applied for post-release 3D integration of MEMS without significantly affecting the mechanical performance of the devices.