Alternating hardmasks for tight-pitch line formation

US10103022B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• John C. Arnold · North Chatham, US
• Anuja E. DeSilva · Slingerlands, US
• Nelson Felix · Slingerlands, US
• Chi-Chun Liu · Altamont, US
• Yann Mignot · Slingerlands, US
• Stuart A. Sieg · Albany, US

Key dates

• Filing date: Mar 20, 2017
• Grant date: Oct 16, 2018
• Expiry date: Mar 20, 2037

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/95
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Methods of forming fins include forming mask fins on a protection layer over a seed layer. Seed layer fins are etched out of the seed layer. Self-assembled fins are formed by directed self-assembly on the seed layer fins. A three-color hardmask fin pattern that has hardmask fins of three mutually selectively etchable compositions is formed using the self-assembled fins as a mask. A region on the three-color hardmask fin pattern is masked, leaving one or more fins of a first color exposed. All exposed fins of the first color are etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into the fin base layer by anisotropically etching around remaining fins of the first color and fins of the third color.