Patent ID: 8673165
Filing Date: 2014-03-18
Classification: H01L

Abstract:
1. A method comprising: forming a multi-level dielectric layer out of a substantially conformal dielectric layer through one or more isotropic etching processes of said substantially conformal dielectric layer, said multi-level dielectric layer having a plurality of regions covering a plurality of mandrels, said plurality of regions of said multi-level dielectric layer having different thicknesses; etching said plurality of regions of said multi-level dielectric layer into spacers by applying a directional etching process, said spacers being formed next to sidewalls of said plurality of mandrels and having different widths corresponding to said different thicknesses of said plurality of regions of said multi-level dielectric layer; removing said plurality of mandrels in-between said spacers; and transferring bottom images of said spacers into one or more layers underneath said spacers.