Method for selective extraction of sacrificial place-holding material used in fabrication of air gap-containing interconnect structures

US6346484B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• John M. Cotte · New Fairfield, US
• Christopher V. Jahnes · Upper Saddle River, US
• Kenneth McCullough · Fishkill, US
• Wayne M. Moreau · Wappingers Falls, US
• Satyanarayana V. Nitta · Poughquag, US
• Katherine L. Saenger · Ossining, US
• John P. Simons · Cold Spring, US

Key dates

• Filing date: Aug 31, 2000
• Grant date: Feb 12, 2002
• Expiry date: Aug 31, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/31111
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

The present invention relates to formation of air gaps in metal/insulator interconnect structures, and to the use of supercritical fluid (SCF)-based methods to extract sacrificial place-holding materials to form air gaps in a structure. Supercritical fluids have gas-like diffusivities and viscosities, and very low or zero surface tension, so SCF's can penetrate small access holes and/or pores in a perforated or porous bridge layer to reach the sacrificial material. Examples of SCFs include CO2 (with or without cosolvents or additives) and ethylene (with or without cosolvents or additives). In a more general embodiment, SCF-based methods for forming at least partially enclosed air gaps in structures that are not interconnect structures are disclosed.