Microhydrodynamic lubrication

Figure 15.16 SIS with no rinse gives a higher removal rate than PA with no rinse due to microhydrodynamic lubrication.

Experiments suggest that two main mechanisms are at work in a successful SIS application, dilution mitigation in exposed pores and valleys, and elimination of microhydrodynamic lubrication at contacts. The latter occurs in processes operating with a fast platen and low down force. The same experiments also provide some suggestive new clues about what may be happening in the gap between the pad and the wafer. 

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