RF pulsing technology in dry etcher had been developed about 20 years ago. But recently as the device node falls below 20nm (pitch size) many etch problems such as profile distortion, poor uniformity control, etc. become critical issue to be cleared. Many commercial dry etchers are currently introducing various pulsing technologies on their process chamber to overcome those process issues. They have claimed many process merits with RF pulsing. However one of the main problems in RF pulsing in mass production fabs lies in slower etch rate and unstable plasma. We also have developed RF pulsing technology on our CCP type dielectric etcher and ICP type conductor etcher. We have tested and optimized many different RF configurations such as RF frequencies pulsing, DC(Direct Current) pulsing and secondary electrode pulsing. One of tested configurations, we have found that secondary electrode DC pulsing with 3 different RF frequencies biased wafer electrode showing higher etch rate with improved mask selectivity as well as controlled bottom CD(critical dimension). Those results might be due to the fact that higher density plasma with higher ion energy is generated by enhanced electron energy distribution function(EEDF) and narrowed high energy ion density with DC pulsing.