Wafer Level Assembly Methods for Complex Pathway Micro-Fluidic PCR Reactor

Micro-fluidic devices were fabricated that amplify DNA segments using the polymerase chain reaction (PCR). These devices employ a unique passive heating methodology that provides ultra-fast fluidic temperature transitions. The devices consist of alternating layers of thermally conductive and insulative layers. The highly thermally conductive layers consist of silicon etched to form vias and micro-channels. The thermally insulative layers were made of polyetherimide layers with laser ablated vias. Individual layers of materials were aligned and joined together to create this device. Novel joining technologies developed for the project included the epoxy specifically targeted for adhesive printing and the mechanical alignment methods. A custom formulated epoxy was created to give a submicron bond line that is controllable, strong, and highly resistant to aqueous and solvent exposure. The bonding temperature was less than 200degC, creating leak-free continuous micro-fluidic pathways. Biocompatible coatings were applied to the entire length of the 600 mm internal pathway before use. The device was used to successfully demonstrate PCR reaction times of less than 5 minutes; this is in comparison to the conventional methods which take several hours.