Understanding the Formation of Circular Ring Defects in Post-CMP Cleaning

Ping Hsu; Roger Luo; Pascal Berar

doi:10.4028/www.scientific.net/SSP.219.153

Paper Titles

Physical Chemistry of Water Droplets in Wafer Cleaning with Low Water Use
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Metal Etch in Advanced Immersion Tank with Precision Uniformity Using Agitation and Wafer Rotation
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Novel Slurry Injection System for Improved Slurry Flow and Reduced Defects in CMP
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Effect of Viscoelasticity of PVA Brush on Friction during Post-CMP Cleaning: A Guideline for Nodule Configuration
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Understanding the Formation of Circular Ring Defects in Post-CMP Cleaning
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Particle Measurement with a Liquid-Borne Particle Counter: Analytical Figures of Merit
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Fluid Flow and Defect Density Considerations when Drying Bumped Wafers Using Spin and Surface Tension Gradient Methods
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Characterization of Cavitation in Ultrasonic or Megasonic Irradiated Gas Saturated Solutions Using a Hydrophone
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Detection of HO₂•/O₂•^- Radicals Formed in Aqueous Solutions Irradiated with Megasonic Waves Using a Cavitation Threshold (CT) Cell Set-Up
p.170

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Understanding the Formation of Circular Ring Defects in Post-CMP Cleaning

Abstract:

Ring type defects are considered to come from scratches by large particles or agglomerated particles during brush scrubbing process on wafers in Post Cu CMP (chemical mechanical polishing) cleaning [1]. However, the mechanism for circular ring defects to appear on wafers still remains a puzzle. Our studies indicated that pH variation during the PCMP process might have a significant effect on altering the surface charge and triggering particle agglomeration. The extent and distribution of particle agglomeration were theoretically and experimentally investigated by zeta potential and particle size analyzer. The results from these studies can provide framework for formulation development to reduce or eliminate ring type defects after PCMP process and improve device yield and performance.