Fluidic self-assembly of micromirrors onto microactuators usingcapillary forces

摘要

The authors discuss the application of self-assembly techniquesnfor positioning microscopic components onto a substrate in a desirednconfiguration. The basis is a fluidic self-assembly technique in whichncapillary forces assemble microparts with submicrometer alignmentnprecision. A heat-curable acrylate-based adhesive is used to provide thencapillary forces for assembly and is then polymerized in a bath of waternat 80°C for 16 h with continuous nitrogen bubbling. The applicationnwe describe is self-assembly of flat silicon micromirrors; ontonsurface-micromachined actuators for use in an adaptive-optics mirrornarray. Photolithography defines shapes of hydrophobic self-assemblednmonolayers for self-assembly. Mirrors with fill factors up to 95% werenassembled. Mirrors 464 Μm in diameter and assembled onto actuatorsnremain flat to within 6 nm rms. This mirror quality would be difficultnto attain without the process decoupling afforded by microassembly. Thengeneral self-assembly approach described here can be applied to partsnranging in size from the nanometer to the millimeter scale and to anvariety of part and substrate materials