UNIT V

fabrication of MEMs

  UNIT V: MICROSYSTEMS AND THEIR FABRICATION Photolithography, Ion implantation, Diffusion and oxidation, Chemical and Physical vapor deposition,etching, Bulk micro manufacturing, Surface Micromachining, The LIGA Process.  Microsystems Fabrication Processes ã To fabricate any solid device component, one must first select materials and adequate fabrication method. ã For MEMS and microsystems components, the sizes are so small that no machine tools, e.g. lathe, milling machine, drilling press, etc. can do the job. There is simply no way one can even grip the work piece. ã Consequently, radically different techniques, non-machine-tool techniques need to be used for such purpose. ã Most physical-chemical processes developed for “shaping” and fabricating ICs are adopted for microsystems fabrications. This is the principal reason for using silicon and silicon compounds for most MEMS and microsystems  – because these are the materials used to produce ICs.  Microfabrication Processes ● Photolithography ● Ion implantation ● Diffusion ● Oxidation ● Chemical vapor deposition ● Physical vapor deposition (Sputtering) ● Deposition by expitaxy ● Etching