Surface treatment

Self Assembling Monolayers

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.

SAM Coating

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

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