Ion implanter for implantation of ions into substrates e.g. semiconductor wafers in electronic device mfr.

摘要

The implanter includes a deceleration lens assembly (9) located between s mass selection flight tube (27) and a substrate holder (11). The lens includes a first electrode (65) at the substrate potential, a second electrode (60) at the flight tube potential and a field electrode (61) between the two at a negative potential to provide focusing. The axial spacing (a) in the beam direction between the two electrodes (65,60) is less than the smallest transverse dimension of the aperture (63) of the field electrode. The lens assembly may be mounted directly opposite the outlet (83) from the process chamber to the vacuum pump to maximise evacuation efficiency.