Patent ID: 8524605

Claim:
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.