Stress locking layer for reliable metallization

US8420537B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Kaushik Chanda · Fishkill, US
• Ronald G. Filippi · Wappingers Falls, US
• Charles C. Goldsmith · Poughkeepsie, US
• Ping-Chuan Wang · Hopewell Junction, US
• Chih-Chao Yang · Glenmont, US

Key dates

• Filing date: May 28, 2008
• Grant date: Apr 16, 2013
• Expiry date: Oct 31, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76883
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Recrystallization and grain growth of metal, such as Cu, is achieved at higher anneal temperatures of 150° C. to 400° C., for example, for short anneal times of five to sixty minutes by forming a metal stress locking layer on the Cu before anneal and chemical-mechanical polishing. The stress locking layer extends the elastic region of the Cu by suppressing atom diffusion to the free surface, resulting in near zero tensile stress at room temperature after anneal. Stress voiding, which creates reliability problems, is thereby avoided. Improved grain size and texture are also achieved. The stress locking layer is removed after anneal by chemical-mechanical polishing leaving the Cu interconnect with low stress and improved grain size and texture.