Metal Oxide-Polymer Composite Particles for CMP Slurries
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Solution Overview
Problem
Chemical mechanical planarization (CMP) processes face challenges in achieving high removal rates while minimizing defectivity and maintaining uniformity, as existing slurries and pads often require trade-offs between removal rate and defectivity, and struggle with residual particle debris and cleaning efficiency.
Innovation Solution
The use of metal oxide-polymer composite particles, which combine the benefits of larger and smaller abrasive particles by embedding metal oxide particles within a polymer core, enhancing removal rates and reducing defectivity through improved contact mechanics and hydrodynamic properties, and facilitating easier cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP slurries with small abrasive particles are used, then removal rate is improved, but defectivity increases due to residual particle debris
Solution Approach 1:
The abrasive system is segmented into two distinct size populations: larger particles (0.5-5 μm) that perform the primary material removal function, and smaller particles (0.01-0.1 μm) that perform the secondary function of cleaning residual debris from the wafer surface. This segmentation allows each particle size to specialize in its optimal function, achieving high removal rates while minimizing defectivity.
Solution Approach 2:
The patent changes the particle size distribution parameter by introducing a bimodal distribution instead of a unimodal distribution. This parameter change enables the system to simultaneously achieve high removal rates (through larger particles) and low defectivity (through smaller cleaning particles), resolving the trade-off between productivity and quality.
2Productivity
If polishing pads with micro-texture for slurry retention are used, then material removal efficiency is improved, but cleaning difficulty increases due to trapped debris
Solution Approach 1:
The cleaning function is extracted from the polishing pad structure and transferred to the slurry composition itself. The smaller abrasive particles in the slurry actively clean the wafer surface by removing residual debris, eliminating the need for separate cleaning operations and avoiding the trap of debris in pad micro-texture.
Solution Approach 2:
The slurry composition performs self-cleaning by incorporating smaller particles that automatically remove residual debris from the wafer surface during the polishing process. This self-service mechanism eliminates the need for external cleaning operations and avoids the problems associated with trapped debris in pad structures.
3Object-affected harmful factors
If larger abrasive particles are used, then defectivity is reduced, but removal rate decreases
Solution Approach 1:
The abrasive system is segmented into two distinct size populations: larger particles (0.5-5 μm) that perform the primary material removal function, and smaller particles (0.01-0.1 μm) that perform the secondary function of cleaning residual debris from the wafer surface. This segmentation allows each particle size to specialize in its optimal function, achieving high removal rates while minimizing defectivity.
Solution Approach 2:
The patent merges the material removal function and the cleaning function into a single slurry composition containing both larger and smaller abrasive particles. This combination allows the system to simultaneously achieve high removal rates (through larger particles) and low defectivity (through smaller cleaning particles), resolving the trade-off between productivity and quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in improved removal rates (up to 50% increase) and reduced defectivity (10-90% decrease), along with enhanced cleaning efficiency and prolonged pad life, while maintaining selectivity and uniformity across larger wafer scales.
Implementation Method 1
CMP slurries generally contain abrasive particles... wafer material is removed by the combined actions of the chemical slurry and abrasive properties of the pad
Implementation Method 2
Both chemical and mechanical actions are generally involved... removal of material from a substrate through chemical and abrasive actions
Data Source
AI summary
CMP processes, tools and slurries utilize metal oxide-polymer composite particles that include metal oxide particles and a polymer core. The metal oxide particles are modified with a modifying agent and are partially or fully embedded within the polymer core. Using these processes, tools and slurries can enhance removal rates, reduce defectivity and increase cleanability with respect to comparable systems and substrates.