DEPOSITION IN DRY-ETCHING GAS PLASMAS

Polymer deposition on Si and SiO2 surfaces has been investigated in CH2F2, CHF3, CF4, and CHClF2 gas plasmas, using a microwave plasma etching system. The dependence of the deposition rate on gas pressure, RF bias power, and substrate temperature was measured at a temperature between -120-degrees-C and 150-degrees-C, The deposition rate increased with decreasing temperature in CH2F2, CHF3, and CHClF2 plasmas. The deposition of polymers occured only below -60-degrees-C in the CF4 plasma. The obtained dependence of the deposition rate on gas pressure was examined in terms of the volume of adsorbed particles. X-ray photoelectron spectroscopy measurement showed that the number of bondings between C and F atoms in deposited polymers increases with decreasing temperature and RF power, and increasing gas pressure.