Large particle counting for quality control of CMP slurries

Conference: ICPT 2007 - International Conference on Planarization / CMP Technology
10/25/2007 - 10/27/2007 at Dresden, Germany

Proceedings: ICPT 2007

Pages: 6Language: englishTyp: PDF

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Nogowski, A.; Stintz, M. (Research Group Mechanical Process Engineering, Institute of Process Engineering and Environmental Technology, TU Dresden, Dresden 01062, Germany)
Barthel, H. (Wacker-Chemie AG, Burghausen 84489, Germany)

The purity of fluids (ultra pure water, chemicals and CMP slurries) has a high relevance for the production of micro- and nano-structures on semiconductor and electronic components. Quality control of these liquids and slurries requires monitoring techniques for the detection of rare large particles, which have been correlated to micro- scratches on wafer surface. Concerning the particle concentration and the main particle size distribution a huge variety of measurement methods and commercial instruments is available. However, the detection of few coarse particles requires a different type of measurement technique. The particle counters, which belong to this class, employ two principle effects: light scattering and light extinction. The measured particle sizes depend on the respective technique, but as well on the sample preparation and dispersion. The authors discuss the characteristics and performances of the above mentioned techniques. In experiments different analyzers were evaluated with respect to high sensitivity, repeatability and resolution for particle standards and commercial CMP slurries (filtered as well as contaminated). Significant deviations in the performance and the sensitivity of scattering and obscuration sensors are observed.