Study of energy broadening of high-brightness ion beams from a surface plasma Penning source and its relevance in ion projection lithography

The energy spread Delta E (Full Width at Half Maximum of the energy distribution) of negative hydrogen ion (H-.) beams has been measured for angular beam intensities (I-Omega) over a range of about 40 to 100 mA/sr. An I-Omega(2/3) dependence of the energy spread is observed. This trend supports the mechanism of energy broadening due to potential energy relaxation. The observed energy spread of less than or similar to 3 eV at I-Omega of about 40 mA/sr projects a favorable scenario toward the demand of a future production-line ion projection lithography system. The maximum value of I-Omega/Delta E(2) = 4 mA/sr eV(2) suggests the possibility of H-. beams for ion microscopy and surface analysis applications also. The H-. ion source is currently operated in pulsed mode (maximum duty of 1% - 1 ms, 10 Hz); cw operation can be achieved by improving the cooling system of the electrodes.