Fine-pitch device lithography using a sacrificial hardmask

US6734096B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Timothy J. Dalton · Ridgefield, US
• Minakshisundaran Balasubramanian Anand · Yokohama, JP
• Michael D. Armacost · Winooski, US
• Shyng-Tsong Chen · Rensselaer, US
• Stephen M. Gates · Ossining, US
• Stephen E. Greco · Lagrangeville, US
• Simon Karecki · Poughkeepsie, US
• Satyanarayana V. Nitta · Poughquag, US

Key dates

• Filing date: Jan 17, 2002
• Grant date: May 11, 2004
• Expiry date: Feb 18, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76826
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method is described for forming a metal pattern in a low-dielectric constant substrate. A hardmask is prepared which includes a low-k lower hardmask layer and a top hardmask layer. The top hardmask layer is a sacrificial layer with a thickness of about 200 å, preferably formed of a refractory nitride, and which serves as a stopping layer in a subsequent CMP metal removal process. The patterning is performed using resist layers. Oxidation damage to the lower hardmask layer is avoided by forming a protective layer in the hardmask, or by using a non-oxidizing resist strip process.