Fabrication and mask design methods using spatial frequency sextupling technique
AssigneeVigma Nanoelectronics
InventorYijian Chen
Life of this patent
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Abstract
Self-aligned sextuple patterning (SASP) processes and mask design methods for the semiconductor manufacturing are invented. The inventions pertain to methods of forming one and/or two dimensional features on a substrate having the feature density increased to six times of what is possible using the standard optical lithographic technique; and methods to release the overlay requirement when patterning the critical layers of semiconductor devices. Our inventions provide production-worthy methods for the semiconductor industry to continue device scaling beyond 15 nm (half pitch).
Claims11
A self-aligned sextuple patterning process comprising:
- a first layer of a first sacrificial material formed over the substrate;
- a hard-mask layer formed over the first sacrificial layer;
- a lithographic step to pattern the resist coated on wafer;
- etching the hard-mask layer and using it as a hard mask for the following etching;
- etching the first sacrificial layer and stripping the hard-mask residue;
- deposition of a CVD layer over the sacrificial features;
- etching the CVD layer to form spacers on the sidewall of sacrificial features;
- using oxygen plasma process to strip amorphous carbon;
- coating a thin film, then BARC and resist on the wafer;
- a lithographic step to pattern the assisting features on resist;
- etching the thin film to form assisting pads on top of oxide spacers;
- depositing a second sacrificial layer;
- etching the second sacrificial layer to form sacrificial spacers;
- depositing a structural layer;
- (optionally) etching the structural layer to form structural spacers;
- coating BARC and resist on the wafer and using a cut mask in a lithographic step to pattern the resist;
- etching to cut the ends of oxide and structural spacers to isolate the lines from each other;
- etching the sacrificial spacers and the assisting pads with dry plasma process or wet solution, leaving sextuple the original density of the first sacrificial features;
- a lithographic step to pattern the final pads on resist (attached to the end of lines for contact landing);
- etching to transfer the final pattern to the substrate.
Dependencies are inferred from the claim text.