Angled multi-step masking for patterned implantation

摘要

An improved method of tilting a mask to perform a pattern implant of a substrate is disclosed. The mask has a plurality of apertures, and is placed between the ion source and the substrate. The mask and substrate are tilted at a first angle relative to the incoming ion beam. After the substrate is exposed to the ion beam, the mask and substrate are tilted at a second angle relative to the ion beam and a subsequent implant step is performed. Through the selection of the aperture size and shape, the cross-section of the mask, the distance between the mask and the substrate and the number of implant steps, a variety of implant patterns may be created. In some embodiments, the implant pattern includes heavily doped horizontal stripes with lighter doped regions between the stripes. In some embodiments, the implant pattern includes a grid of heavily doped regions.

主权项

1. A method of implanting a pattern into a substrate, comprising:
placing a mask, having at least one aperture, in a path of an ion beam between said substrate and an ion source, wherein said mask has a fixed spatial relationship to said substrate; rotating said substrate at a first tilt angle relative to said ion beam; exposing said substrate to said ion beam at a first tilt angle while maintaining said fixed spatial relationship between said substrate and said mask, thereby implanting ions in a first region of said substrate aligned with said aperture when tilted at said first tilt angle; rotating said substrate and said mask at a second tilt angle relative to said ion beam; and exposing said substrate to said ion beam at a second tilt angle while maintaining said fixed spatial relationship between said substrate and said mask, thereby implanting ions in a second region of said substrate, aligned with said aperture when tilted at said second tilt angle; whereby a portion of said first region and a portion of said second region overlap, creating a heavily implanted third region, the third region having a higher implant dose than the first region and a second region outside of the third region.