REDUCING PHOTORESIST LAYER DEGRADATION IN PLASMA IMMERSION ION IMPLANTATION

摘要

A method, of plasma immersion ion implantation of a workpiece having a photoresist mask on its top surface prevents photoresist failure from carbonization of the photoresist. The method includes performing successive ion implantation sub-steps, each of the ion implantation sub-steps having a time duration over which only a fractional top portion of the photoresist layer is damaged by ion implantation. After each one of the successive ion implantation sub-steps, the fractional top portion of the photoresist is removed while leaving the remaining portion of the photoresist layer in place by performing an ashing sub-step. The number of the successive ion implantation sub-steps is sufficient to reach a predetermined ion implantation dose in the workpiece,