Tribological and removal rate characterization of colloidal silica ILD CMP processes

A. Philipossian, M. Sugiyama, D. King, L. Charns, J. Degraffenreid, H. Nguyen-Ngoc

Research output: Contribution to conferencePaper

Abstract

Frictional analysis was used to determine the extent of normal and shear forces during CMP and help identify and compare the tribological mechanisms associated with using colloidal silica and fumed silica slurries for ILD CMP applications. Regardless of the type or flow rate of the slurry, the tribological mechanism remained in 'boundary lubrication' over a wide range of Sommerfeld Numbers. Spectral analysis of friction data was effectively used to quantify the extent of contact between the abrasive particles, the pad and the wafer in terms of stick-slip phenomena. Results indicated a 3-fold increase in the 'hydrodynamic chattering' of the process when a fumed silica slurry was used instead of a colloidal silica slurry. These trends were consistent with previous reports indicating an increase in the amount of contact and pad wear associated with fumed silica slurries. The colloidal slurry resulted in up to 35 percent higher removal rate compared to fumed silica. Increasing colloidal silica slurry flow rate by 25 percent resulted in a 10 percent drop in removal rate and possibly an 8 percent drop in COF. To confirm the validity of the slight drop in COF, real-time temperature mapping of the pad surface during CMP was employed. Results indicated that at the lower flow rate, the pad surface temperature was higher by about 1 degree Celsius possibly due to a greater amount of heat dissipation caused by larger drag forces.

Original languageEnglish (US)
Pages261-269
Number of pages9
StatePublished - Dec 1 2003
EventChemical Mechanical Planarization VI - Proceddings of the International Symposium - Orlando, FL., United States
Duration: Oct 12 2003Oct 17 2003

Other

OtherChemical Mechanical Planarization VI - Proceddings of the International Symposium
CountryUnited States
CityOrlando, FL.
Period10/12/0310/17/03

ASJC Scopus subject areas

  • Engineering(all)

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    Philipossian, A., Sugiyama, M., King, D., Charns, L., Degraffenreid, J., & Nguyen-Ngoc, H. (2003). Tribological and removal rate characterization of colloidal silica ILD CMP processes. 261-269. Paper presented at Chemical Mechanical Planarization VI - Proceddings of the International Symposium, Orlando, FL., United States.