Patent Number: 
Section: abstract

An ion implantation apparatus is disclosed in this invention. The ion implantation apparatus includes a target chamber for containing a target for implantation and an ion source chamber includes an ion source with a mass filter for generating an ion beam with certain mass and original energy. The ion source chamber further includes beam deceleration optics for decelerating the ion beam from the original energy to the desired final energy. The ion beam apparatus is able to accurately direct low energy ions to a target wafer. The beam deceleration optics further includes a plurality of electrodes for generating an electric field for spreading the charged ion beam over an angular range to accurately control the trajectory paths of ions of different energy levels. The purpose is to eliminate the energy contamination by more accurately controlling the energy range of the charged ions that reach the target for implantation and to block the neutralized particle and ions of higher energy from reaching the target for implantation.