Abstract: An ion implantation apparatus includes a charge neutralizer having a control circuit which controls the quantity of secondary electrons irradiating a semiconductor wafer. Electrons are generated in response to a direction of movement of a semiconductor wafer to neutralize positive charge on the semiconductor wafer. The apparatus can neutralize the positive charge homogeneously and prevent electrical breakdown of the semiconductor wafer.

Abstract: An ion implanter encloses a semiconductor substrate adjacent to a fixing member which retains a semiconductor substrate on a supporting bed. The ion implanter includes a ring electrode for generating secondary electrons in response to incident ions and a cup-like electrode for directing the secondary ions to the semiconductor substrate. The ring electrode is negatively biased with respect to the supporting bed and the cup-like electrode surrounds the outer edge of the semiconductor substrate. The ion implanter increases the quantity of the secondary electrons produced and efficiently directs them to the semiconductor substrate. The semiconductor substrate which is electrically charged by implanting ions is neutralized, preventing dielectric breakdown from occurring in an insulating film.