The paper shows the importance of nano-roughening on the bonding interface to the reliability enhancement of adhesive bond for ensuring the continuation of packaging shrinkage from MEMS to NEMS. The roughening is realized via a nonuniformly etching characteristic of PR which is etched and then utilized as an etching mask for following silicon etching process. Ultraviolet adhesive for silicon-to-glass bonding is utilized for the verification of the nano-roughening effect on NEMS hermetic encapsulation. The average roughnesses of the silicon substrate before and after roughening are 0.4 nm and 12.4 nm, respectively. Experimental results show that the roughness increase of silicon substrate can effectively provide more than 30% bonding strength enhancement and 30% leakage reduction. In addition, stamp-and-stick test shows that nano-roughening indeed provides a better adhesive characteristic that can further ensure the success of the stamp-and-stick process for nano/microfabrication.
- Hermetic encapsulation
- Nano-electromechanical systems (NEMS) manufacture
- Scaling rule
- Ultraviolet (UV) adhesive bonding