Fabrication of 3-D microstructures with permanent dielectric dry film

摘要

Smarter and cheaper encasing of devices is essential tornbring packaging costs down. Two different types of packagesrnare described in this paper. Both use wafer level processesrnwhich make them very cost effective.rnIn the first approach dry film resist functions as a glue andrnas a spacer at the same time. Frames of dry film resist arernstructured on the cap wafer by lamination andrnphotolithography. This wafer is then bonded with a wafer-towafer-rnbonder onto the device wafer. Finally the stack is diced.rnIn the second approach, frames of photopolymer arernstructured on the device wafer. In the next step another layerrnof polymer is laminated on top of it. The second layer is thenrnphoto-structured to form the “roof” of the housing while thernframe works as its “side walls”.rnBoth packages can be used for encasing of for examplernSAW or BAW filters. The same processes can be used withrndifferent designs to create fluidic structures e.g. nozzles in inkrnprint head or for medical application like lab-on-chip.