A COMPARISON OF HDP SOURCES FOR POLYSILICON ETCHING

As part of Bell Laboratories' research effort to develop a sub-0.35-mu m design rule process, three commercially available high-density plas ma (HDP) sources were evaluated for 0.35-mu m polysilicon gate etch. H elicon, helical resonator, and multipole electron cyclotron resonance sources were alternately mounted in pairs onto single-wafer etching ch ambers attached to a central robotic hub. This custom system design re moved all other variables from the evaluation of the sources. All thre e plasma sources generated uniform high ion densities at low pressures , and allowed for the development of an optimized etch process.