An optimized labyrinth sealing for MEMS stacking and V-Groove "Particle trap" for particle free MEMS devices
Original Publication Date: 2004-Jun-21
Included in the Prior Art Database: 2004-Jun-21
AbstractDisclosed is the implementation of a “Particle trap” within MEMS (Micro Electro Mechanical Systems) devices. The disclosed embodiment shows the creation of elaborated labyrinth paths with functions of trapping loose particles that may reach critical areas where they would cause MEMS malfunctions.
An optimized labyrinth sealing for MEMS stacking and V -Groove "Particle trap" for particle free MEMS devices
The present publication implements V-groove trenches into an "Elaborate sealing system" used in stacked MEMS. These devices are sensitive to particle contamination that can cause mechanical blockage of the thin and small moving features present in the MEMS configurations.
Particles can be released from a variety of possible sources, they can be left on parts by previous process steps or being a byproduct of process steps, they can also be a result of material phase changes or for example introduced by human presence in the MEMS assembly/production environments.
The original concept of labyrinth sealing alone uses structures, like vertical mechanical elements creating narrow gaps. The possibility for a loose particle to overcome a narrow passage is low, and it becomes smaller when the number of narrow gaps is increased. The number of those elements though reduces the overall possibility of particles penetration into critical areas of the MEMS do not null the probability of this occurrence.
In a specific embodiment a new feature has been added to the Labyrinth sealing. The new structure is called "Particle trap". This is a V-Groove channel etched into the Si of the MEMS with the duty of trapping the falling particles. Once they fall into the groove, due to their odd shape and the converging vertical walls of the groove, they remain trapped by mechanical fri...