Self Assembling Monolayers SAM
Surface stiction is a major problem during fabrication of MEMS components, such as silicon sensors, microactuators or microfludic devices. In addition, the same phenomena are a limiting factor for reliability and lifetime of these components on the customer’s side.
The gas-phase SAM (self-assembling monolayers) coating process for micro components reduces or eliminates adhesion related phenomena. Essential for the industrial use of hydrophobic SAM-based coatings is the existence of a process suitable to be integrated in an industrial environment for fabrication of large volumes (serial production). microFAB has developed such a process together with international partner companies (Europlasma, Sonion A/S) and institutes (IMSAS Bremen, MIC/DTU Lyngby) in the scope of the European funded CRAFT project called HydroSurf.
Benefits of SAM coating
- Avoidance of sticking during use of MEMS devices with delicate structures, like suspended membranes, movable comb structures or cantilevers
- Avoidance of sticking during wet processing of wafers with suspended MEMS structures
- Generation of a hydrophobic surface displaying low surface energy and high contact angles > 110°, similar to Teflon
- Stabilization of the treated MEMS surface by low-temperature steps (full back-end process compatibility)
- Excellent mechanical and thermal stability (up to 400°C, therefore compatible to standard-packaging-processes including solder reflow)
- Selective coating of hydrophilic surfaces with OH-bonds only (metal pads are not coated)
- Serial production compatible high-throughput, low-cost batch process