Method for removal of hard mask used to define noble metal electrode

US6420272B1 · kind B1 · utility

Assignees

• Infineon Technologies AG · DE
• International Business Machines Corporation · US

Inventors

• Hua Shen · Beacon, US
• David E. Kotecki · Hopewell Junction, US
• Satish D. Athavale · Fishkill, US
• Jenny Lian · Oshima, JP
• Gerhard Kunkel · Radebeul, DE
• Nimal Chaudhary · Poughkeepsie, US

Key dates

• Filing date: Dec 14, 1999
• Grant date: Jul 16, 2002
• Expiry date: Dec 14, 2019

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/682
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

In semiconductor dynamic random access memory circuits using stacked capacitor storage elements formed using high permittivity dielectric material, it is typical to form the stacked capacitors using noble metal electrodes. Typically, the etching process for the noble metal electrodes requires the use of a hard mask patterning material such as silicon oxide. Removal of this hard mask frequently results in damage to the dielectric surface surrounding the patterned noble metal electrode. A method of removing the hard mask material without damaging the surrounding surface includes the steps of: depositing a soft mask photoresist material over the composite surface, including the hard masked covered noble metal electrode and the dielectric surface, in a manner such that the soft mask material is thinner over the region of the noble metal electrode; removing the portion of the soft mask material over the noble metal electrode leaving the soft mask material over the dielectric surface; etching the hard mask material with the soft mask material protecting the dielectric surface; and removing the remaining portion of the soft mask material.