Method to improve indium bump bonding via indium oxide removal using a multi-step plasma process

US8163094B1 · kind B1 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• H. Frank Greer · Pasadena, US
• Todd J. Jones · Altadena, US
• Richard Vasquez · Altadena, US
• Michael E. Hoenk · Pasadena, US
• Matthew R. Dickie · Altadena, US
• Shouleh Nikzad · Valencia, US

Key dates

• Filing date: Jul 23, 2009
• Grant date: Apr 24, 2012
• Expiry date: Aug 16, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/14
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A process for removing indium oxide from indium bumps in a flip-chip structure to reduce contact resistance, by a multi-step plasma treatment. A first plasma treatment of the indium bumps with an argon, methane and hydrogen plasma reduces indium oxide, and a second plasma treatment with an argon and hydrogen plasma removes residual organics. The multi-step plasma process for removing indium oxide from the indium bumps is more effective in reducing the oxide, and yet does not require the use of halogens, does not change the bump morphology, does not attack the bond pad material or under-bump metallization layers, and creates no new mechanisms for open circuits.