Investigation of the kinetics of tungsten chemical mechanical polishing in potassium iodate-based slurries. 2: Roles of colloid species and slurry chemistry
- Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering
- Sandia National Labs., Albuquerque, NM (United States). Microelectronics Development Lab.
The authors investigated the role of colloid species and slurry chemistry in tungsten chemical mechanical polishing. Specifically, they measured polish rate and process temperature in potassium iodate-based slurries as a function of colloid species and concentration, slurry pH, and potassium iodate concentration, as well as polish pressure and polish rotation rate. They investigated slurries containing yttrium-, zirconium-, cerium-, and aluminum-based oxide and hydroxide colloids. They found that the colloid species had a large effect on polish rate and process temperature. The colloids showed two orders of magnitude in the polish rate range from {approximately}15 to {approximately}1975 {angstrom}/min under otherwise identical experimental conditions (same polisher, pad, slurry chemistry, pressure, and rotation rates). Colloids of the same metal species from different sources also showed a large range in polish rates. Process temperature was a function of colloid species, however, the trend in polish rate did not always follow that of process temperature. Both polish rate and process temperature were dependent on potassium iodate concentration and slurry pH (controlled with a buffer). The authors also introduce a heuristic polish mechanism to investigate the role of the colloid surface chemistry and its interaction with the tungsten surface. The data indicate that the surface characteristics of the colloid and how this surface interacts with the tungsten surface play a significant role in the mechanism of tungsten removal during polish.
- Research Organization:
- Sandia National Laboratory
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 354423
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 5 Vol. 146; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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