Agglomerate Separation in CMP Slurry Delivery

Chemical Mechanical Planarization (CMP) slurries contain carefully sized nanometer-scale abrasive particles (such as silica, alumina, or ceria) held in a precise chemical balance. During transportation, storage, and pumping, continuous shear stress can cause these fine particles to clump together into larger agglomerates ($>1 \mu m$). If these oversized particles reach the wafer, they cause micro-scratches and defect clusters that destroy active circuit features.

       Raw Slurry Stream (Agglomerates + Target Particles)
                             │
                             ▼
     +-----------------------------------------------+
     | Depth Filter Matrix (Asymmetric Pore Network) |
     |                                               |
     |   (X) Agglomerates Trapped in Matrix Depth   |
     |   (•) Target Particles Pass Through Safely    |
     +-----------------------------------------------+
                             │
                             ▼
             Purified Slurry to Polishing Tool

CMP slurry filters must selectively capture these oversized agglomerates while allowing functional, properly sized abrasive particles to pass through unimpeded.

Filter Media and Morphological Design

Achieving selective filtration requires careful membrane design and chemical compatibility:

• Asymmetric Depth Filters: Constructed from micro-fibers, these filters feature gradient pore structures that narrow toward the inner core. Larger agglomerates are trapped in the outer layers, while smaller target abrasives flow through without clogging the filter matrix.

• Low-Shear Hydraulic Flow Paths: The internal channels are designed to minimize flow turbulence, preventing shear forces from causing further particle clumping within the filter housing.

• Polymeric Inertness: Constructed using high-purity polypropylene, polyethylene, or PTFE, these media prevent metal ion leaching and withstand exposure to aggressive acidic or basic slurry chemistry.

Source - https://www.wiseguyreports.com/reports/cmp-slurry-filter-market