Development of photoresist ashing process in an ICP with periodic axial magnetic field

주기적인 축방향 자기장을 추가한 유도결합형 플라즈마 장치에서의 감광제 제거공정 개발

Low frequency(<100Hz) weak magnetic field(<20gauss) is applied axially to an inductively coupled oxygen plasma(ICP), and its plasma characteristics are monitored by OES(Optical Emission Spectroscopy) and Langmuir probe. It is found that periodic magnetic field enhances ashing rate by 25％ and improves its uniformity upto 4.5％ over 8" wafer. From electron energy distribution function, both low and high energy electrons are identified and relative abundancy is found to be controlled by the applied frequency. Moreover, it is observed that ionization and dissociation species are varied with applied frequency. We insert an aluminium baffle in the chamber to get better uniformity and less plasma damage.