Localized plastic bonding for micro assembly, packaging and liquid encapsulation

Localized plastic bonding schemes for plastics-to-silicon, plastics-to-glass, and plastics-to-plastics assembly, packaging and liquid encapsulation have been successfully demonstrated. Aluminum thin films are deposited and patterned as resistive heaters for the purpose of localized heating and bonding. In the experiments, plastic thin films are successfully bonded on silicon, glass, and plastic substrates in 0.25 seconds under a contact pressure of 0.4 MPa. Local temperature at the bonding interface can reach more than 140/spl deg/C for bonding and the global substrate remains at room temperature. The approach of localized heating for bonding of plastic materials while maintaining low temperature globally enables direct sealing of polymer based MEMS processing without using additional adhesive and without damaging pre-existing, temperature-sensitive substances on the bonding substrate. Water encapsulation by plastics-to-plastics bonding is performed to demonstrate the capability of low temperature processing. As such, this technique can be applied broadly in plastic assembly, packaging and liquid encapsulation for microsystems, including microfluidic devices.