Abstract: A method for pretreatment of a photoresist layer adhered to a semiconductor wafer prior to charged particle beam processing. The method includes bombarding the photoresist layer with ions which are electrically inactive with respect to the wafer. Suitable ions include ions of the noble gases. The pretreatment method causes rapid photoresist outgassing and carbonization without altering the electrical properties of the wafer. Outgassing during subsequent processing is thereby reduced. The pretreatment method is particularly applicable to ion implantation wherein dose measurement errors resulting from photoresist outgassing are reduced. The pretreatment method is performed at high current to minimize the effect on system throughput.

Abstract: Method of and apparatus for scanning a charged particle beam over a semiconductor wafer in a prescribed pattern. A triangular waveform, including alternating positive and negative ramp portions of constant slope and controllable time durations, is applied to a horizontal deflection system and produces horizontal scanning of the beam. The time durations of the ramp portions determine the length of the horizontal scan lines and are controlled according to a predetermined sequence so as to provide the prescribed pattern. The triangular waveform is provided by an integrator which receives a square wave from a frequency source of controllable frequency. The predetermined sequence is stored in a read only memory which controls the frequency of the frequency source. At the completion of each ramp portion, a voltage applied to a vertical deflection system is incremented so as to step the beam vertically up or down.