Removal Characteristics of Resists Having Different Chemical Structures by Using Ozone and Water

Abstract

We investigated an environmentally friendly resist removal method using ozone and water (wet ozone). The resist removal rate was optimum when the temperature of the wet ozone was 83 °C and that of the substrate was 78 °C. Novolak resin of a positive type of novolak resist base polymer has a carbon–carbon double bond in the main chain, so Novolak resin reacted easily with ozone. The resulting removal rate of the novolak resist was about 1.1 µm/min, which was the highest removal rate among novolak, KrF and ArF resists. For all implanted ion species (B, P, and As), all the resist with ions of 5×1013 atoms/cm2 could be removed. Resist with 5×1014 atoms/cm2 As and P ions could not be removed at al, but resist with B ion could be removed. The energy to harden the resist of B ion was less than that to harden P and As ions, because B ion is lighter than the other ions. All the resist with ions of 5×1015 atoms/cm2 could not be removed.