Photoresist Removal Using Reactive Oxygen Species Produced by an Atmospheric Pressure Plasma Reactor

Abstract

An atmospheric pressure (AP) plasma reactor driven by kHz sinusoidal power is developed to investigate effective removal of the photoresist (PR). This reactor can generate oxygen (O) and hydroxyl (OH) radicals simultaneously by introducing small quantities of oxygen (O 2 ) gas and hydrogen peroxide (H 2 O 2 ) vapor along with the discharge gas. To investigate the effects of O and OH radicals on AP-plasma etching, Helium/O 2 , helium/O 2 /H 2 O 2 , argon/O 2 and argon/O 2 /H 2 O 2 plasmas are generated and tested. The PR layer with a thickness of 1.6 μ m is completely removed within 20 s using AP helium/O 2 plasma, and the PR is confirmed to chemically disappear by Fourier transform infrared (FT-IR) measurement. In this case, the etch rate is calculated as several tens of nm/s. When AP argon/O 2 plasma is used, the PR etch rate is lowered to several nm/s, and long-duration plasma treatment for PR removal damaged the silicon substrate without complete PR removal.