Dry etch polysilicon removal for replacement gates

US8673759B2 · kind B2 · utility

Assignee

• GlobalFoundries Inc. · KY

Inventors

• Chris M. Prindle · Dresden, DE
• Klaus Hempel · Dresden, DE
• Andy Wei · Queensbury, US

Key dates

• Filing date: Feb 17, 2012
• Grant date: Mar 18, 2014
• Expiry date: Apr 18, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/68
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Semiconductor devices are formed with a gate last, high-K/metal gate process with complete removal of the polysilicon dummy gate and with a gap having a low aspect ratio for the metal fill. Embodiments include forming a dummy gate electrode on a substrate, the dummy gate electrode having a nitride cap, forming spacers adjacent opposite sides of the dummy gate electrode forming a gate trench therebetween, dry etching the nitride cap, tapering the gate trench top corners; performing a selective dry etch on a portion of the dummy gate electrode, and wet etching the remainder of the dummy gate electrode.