Method of implanting a substrate and an ion implanter for performing the method

Abstract

An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Description

technical field [0001] The present invention relates to a method of implanting a substrate wherein the relative movement between the substrate and the implant beam is controlled to maintain a desired and uniform dose of implanted nuclides over the surface of the substrate. The invention also relates to an ion implanter suitable for carrying out the method. Background technique [0002] In a typical ion implanter, an ion beam of small cross-section containing the desired species is scanned relative to the substrate to be implanted, usually a semiconductor wafer. [0003] The beam may be scanned in two dimensions relative to a stationary wafer, or the wafer may be scanned in two dimensions relative to a stationary beam. Hybrid scanning techniques also exist, where the beam is scanned in one dimension while the wafer is mechanically scanned in a second, usually orthogonal, direction. [0004] Each technique has advantages and disadvantages. For batch processing of semiconduc...

AI Technical Summary

Problems solved by technology

By controlling the speed of this mechanical movement, the dose uniformity across the wafer surface is guaranteed in the direction of the mechanical movement of the wafer, but the mechanical movement is always much slower than the beam scanning speed

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