Polishing Slurry for Tungsten Films
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Solution Overview
Problem
Current polishing slurry compositions for tungsten films in semiconductor processes fail to achieve adequate planarization, leading to metal short circuits and etching defects due to tungsten topography issues, and are not optimized for high integration processes.
Innovation Solution
A polishing slurry composition comprising a mixture of three types of abrasive particles with specific size ranges and a controlled contact area between 0.5 and 0.9, along with an oxidizer, to improve the peak-to-valley roughness and planarization degree of tungsten films, reducing surface defects and enabling high integration processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing slurry compositions are used for tungsten films, then the polishing process can be performed, but the planarization degree is insufficient leading to metal short circuits and etching defects
Solution Approach 1:
The patent uses a composite slurry composition containing multiple types of abrasive particles (colloidal silica, glass beads, ceramic particles) with different material properties and size distributions. This composite approach allows the slurry to simultaneously achieve high planarization degree and prevent metal short circuits by combining the planarizing effect of smaller particles with the scratch-prevention capability of larger particles, resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
The patent optimizes multiple parameters including abrasive particle size distribution (d10, d50, d90 values), concentration ratios of different abrasive types, and slurry pH level. By systematically adjusting these parameters, the slurry achieves the dual goal of improving planarization degree to prevent short circuits while maintaining reliability through controlled removal ratios and surface quality
2Productivity
If polishing slurry is optimized for high polishing speed, then productivity increases, but the planarization degree becomes relatively low
Solution Approach 1:
The patent segments the abrasive particle population into multiple size groups (fine particles for planarization, medium particles for material removal, coarse particles for scratch prevention). This segmentation allows each particle size range to perform its specialized function simultaneously, achieving both high polishing speed through efficient material removal by medium particles and high planarization degree through fine particle action, thus resolving the productivity-precision contradiction
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different particle size components within the slurry. Smaller particles (2-10 μm) are optimized for local planarization in valleys, while medium particles (10-50 μm) handle bulk material removal on peaks, and larger particles (50-200 μm) prevent scratches. This localized functional differentiation enables simultaneous achievement of high polishing speed and excellent planarization
3Productivity
If the contact area between abrasive particles and tungsten film is increased, then the removal ratio increases, but the peak-to-valley roughness may not be sufficiently reduced
Solution Approach 1:
The patent creates a dynamic particle distribution system where particles of varying sizes are continuously redistributed during polishing. As polishing progresses, smaller particles fill valleys and larger particles are gradually worn down, creating a self-adjusting system that maintains optimal contact area distribution. This dynamic behavior allows the slurry to achieve high removal ratios through increased overall contact area while simultaneously reducing peak-to-valley roughness through the penetrating action of smaller particles in low-contact-area regions
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
The composition effectively reduces peak-to-valley roughness to 100 nm or less, achieves a removal ratio of 35% to 70%, and enhances the planarization degree, thereby improving tungsten film topography and reducing metal short circuits and etching defects, facilitating next-generation semiconductor processes.
Implementation Method 1
A polishing slurry composition including at least two types of abrasive particles among first abrasive particles, second abrasive particles, and third abrasive particles, and an oxidizer
Implementation Method 2
A polishing slurry composition including at least two types of abrasive particles among first abrasive particles, second abrasive particles, and third abrasive particles, and an oxidizer
Data Source
AI summary
A polishing slurry composition is provided. The polishing slurry composition includes at least two types of abrasive particles among first abrasive particles, second abrasive particles, and third abrasive particles, and an oxidizer. A peak-to-valley roughness Rpv decreases when a contact area between the abrasive particles and a tungsten-containing film increases.