Abstract
The selective dissolution of thin copper oxide films grown on copper in semi-aqueous formulations containing dimethyl sulfoxide (DMSO), ammonium fluoride (NH4F) and water was studied. Optimization of the formulations was carried out by systematic evaluation of the effect of solvent content and pH on the removal rates of copper oxide films and selectivity towards copper and carbon doped oxide (CDO) low k dielectric film. Copper oxide removal rate of ∼180 /min with a selectivity of ∼130:1 towards copper and ∼20:1 selectivity towards CDO was obtained in a formulation containing 29% DMSO, 1% NH4F and 70% H2O at pH 4. Electrochemical impedance spectroscopy studies were performed on this system and the data were analyzed to characterize the copper oxide/electrolyte interface with the ultimate objective of developing an end point detection technique for copper oxide removal.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1689-1695 |
| Number of pages | 7 |
| Journal | Microelectronic Engineering |
| Volume | 87 |
| Issue number | 9 |
| DOIs | |
| State | Published - Nov 2010 |
| Externally published | Yes |
Keywords
- BEOL cleaning
- Copper oxide removal
- Electrochemical impedance spectroscopy
- SAF chemical system
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering