This presentation examines how shear stress within a CMP (Chemical Mechanical Polishing) Slurry Dispense System affects slurry quality and wafer yield. During mixing, circulation, and filtration, high shear stress causes slurry particles to aggregate, generating Large Particle Counts (LPC) that scratch wafer surfaces and reduce yield. In contrast, low shear stress keeps particles well-dispersed, ensuring stable slurry properties and consistent material removal.

A low-shear-stress design is introduced, replacing traditional high-speed jet agitation (with 3 mm tiny-hole flow) with a low-speed mechanical rotation that creates a large rotating region, dramatically reducing shear intensity and component damage risk. CFD simulations evaluated tank bottom angles (10°, 20°, 30°) and stirring speeds (100, 500, 1000 rpm) to identify optimal mixing parameters.

The SDS architecture separates mixing and filtration into independent loops using a patented low-shear mixing pump alongside maglev filtration pumps, improving uniformity, filtration efficiency, and flow stability. A zero-residue full-loop cleaning function applies custom DIW pressure with N₂ cycle purge to eliminate dead-end and branch-line residues. Stability data show variability levels for conductivity, pH, specific gravity, and H₂O₂ well below traditional out-of-control and out-of-spec thresholds, confirming superior slurry quality and reduced wafer scratch rates.