LARGE-DIAMETER MICROWAVE SF6 PLASMA PRODUCTION WITH RING-SHAPED PERMANENT-MAGNETS

A large diameter and uniform microwave plasma (about 30 cm in diameter ) over 10 cm from the source has been produced by scaling up a prelimi narily proposed device with an annular slot antenna and satisfying the ECR (electron cyclotron resonance) condition in a chamber with neodym ium ring-shaped permanent magnets. The spatial structure of the plasma density in both non-reactive Ar and reactive SF6 gases was obtained b y a Langmuir probe. The tentative etching of silicon (Si) was performe d in the SF6 microwave plasma. The spatial profile of the etch rate in the radial direction was found to be similar to that of electron dens ity in the SF6 plasma. The uniformity of etch rate was within 2.5% at the position where electron density profile reached the best uniformit y (similar or equal to 5%). The etching profile of the poly-Si pattern in the microwave plasma using pure SF6 gas was also observed by a sca nning electron microscope (SEM).