New methods for liquid encapsulation in polymer MEMS structures

Two methods for encapsulating liquid phase materials in cavity structures fabricated by polymer MEMS technologies are reported. Potential application fields include optical devices with liquid-base components. Most of existing methods for liquid encapsulation are based on UV-curable resins, which forces restrictions on choice and handling of liquids to be confined. The proposed approaches utilize polymer thermal bonding and stiction, respectively, aiming for more simple and less restrictive processes than the existing methods. Experiments were conducted with these two approaches using DI water as working liquid to be encapsulated, and parylene as structural polymer material. The basic concepts of both methods were confirmed by the results. Measures to improve long term stabilities were discussed.