Taiwan Semiconductor Manufacturing Comp. Ltd.

Bao-Ju Young

Chia-Shiung Tsai

Ying-Ying Wang

Ming-Hsin Huang

A new method of forming a bi-layer photoresist mask with a reduced critical dimension bias between isolated and dense lines and reduced edge roughness is described. A layer to be etched is provided on a semiconductor substrate wherein the surface of the layer has an uneven topography. The layer to be etched is coated with a first planarized photoresist layer which is baked. The first photoresist layer is coated with a second silicon-containing photoresist layer which is baked. Portions of the second photoresist layer not covered by a mask are exposed to actinic light. The exposed portions of the second photoresist layer are developed away. Then, portions of the first photoresist layer not covered by the second photoresist layer remaining are developed away in a dry development step wherein sufficient SO gas is included in the developing recipe to reduce microloading to form a bi-layer photoresist mask comprising the first and second photoresist layers remaining. Thereafter, the bi-layer photoresist mask is ashed to smooth its sidewall edges. This completes formation of a bi-layer photoresist mask having a reduced critical dimension bias between isolated and dense lines and reduced edge roughness.

Dry development process for a bi-layer resist system

A new method of etching metal lines without polymer residue using a composite hard mask and two-step hard mask etching process is described. An insulating layer is provided on a semiconductor substrate. A first barrier metal layer is deposited overlying the insulating layer. A metal layer is deposited overlying the barrier metal layer. A second barrier metal layer is deposited overlying the metal layer. A composite hard mask layer is deposited overlying the second barrier metal layer. A photoresist mask is formed overlying the composite hard mask layer having openings where openings are to be made within the metal layer. First, the composite hard mask layer is partially etched away where it is not covered by the photoresist mask. Second, most of the composite hard mask layer is overetched away leaving a patterned hard mask and a portion of the hard mask layer within the openings whereby a polymer is formed within the openings. Since the second barrier metal layer is covered by the hard mask layer within the openings, the polymer does not contain metallic atoms. The polymer is removed. Thereafter, the photoresist mask is removed. The metal layer and barrier metal layers not covered by the patterned hard mask are etched away to form metal lines wherein the hard mask layer within the openings is also removed.

Polymerless metal hard mask etching

A new method of forming a bi-layer photoresist mask with a reduced critical dimension bias between isolated and dense lines and reduced edge roughness is described. A layer to be etched is provided on a semiconductor substrate wherein the surface of the layer has an uneven topography. The layer to be etched is coated with a first planarized photoresist layer which is baked. The first photoresist layer is coated with a second silicon-containing photoresist layer which is baked. Portions of the second photoresist layer not covered by a mask are exposed to actinic light. The exposed portions of the second photoresist layer are developed away. Then, portions of the first photoresist layer not covered by the second photoresist layer remaining are developed away in a dry development step wherein sufficient SO,gas is included in the developing recipe to reduce microloading to form a bi-layer photoresist mask comprising the first and second photoresist layers remaining. Thereafter, the bi-layer photoresist mask is ashed to smooth its sidewall edges. This completes formation of a bi-layer photoresist mask having a reduced critical dimension bias between isolated and dense lines and reduced edge roughness.

Growing community of inventors

I Lan, Taiwan

Bao-Ju Young