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

Abstract

The energy spread ΔE (Full Width at Half Maximum of the energy distribution) of negative hydrogen ion (H−) beams has been measured for angular beam intensities (IΩ) over a range of about 40 to 100 mA/sr. An IΩ23 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 ≲ 3 eV at IΩ 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 IΩΔE2 = 4 mA/sr eV2 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.