Method of forming ion implants self-aligned with a cut

A method of implanting impurity ions in regions lying laterally spaced apart within a first stratum of a semiconductor body and offset and self-aligned with the edges of an opening formed within a second stratum of material lying above said first stratum, said method comprising:

• (a) providing a semiconductor body having a first stratum therein and providing a second stratum of material adjacent to said first stratum,
• (b) superimposing successive layers of a thin negative photoresist and a thicker positive photoresist over said second stratum in that order,
• (c) removing only selected spaced portions of said positive photoresist layer by photolithographic means to produce voids therein,
• (d) subjecting the structure thus formed to impurity ions of such velocity that impurity ions deposit in laterally spaced implanted regions of said first stratum that are aligned with said voids but are blocked from regions underlying said positive photoresist layer,
• (e) removing the remaining positive photoresist layer and the underlying part of negative photoresist layer, and
• (f) while using the remaining negative photoresist layer as a mask, removing material of said second stratum that is uncovered by said negative photoresist layer to produce an opening within said second stratum that is self-aligned with and disposed between said laterally spaced regions of implanted impurity ions.