CMP Slurry with Nitrate-Modified Ceria Particles
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Solution Overview
Problem
The CMP process faces challenges in reducing defect sizes to maintain high yield and productivity, as smaller polishing particles decrease the polishing rate, and existing solutions like polishing accelerators can degrade dispersion stability and require material-specific adjustments.
Innovation Solution
A slurry composition for CMP that includes ceria or other ceramic particles with surface-modifying functional groups like nitrate, carbonate, sulfate, or oxalate, which are dispersed in a medium without oxidizers or polishing accelerators, allowing for controlled pH and particle size to enhance polishing rates without compromising stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the size of polishing particles is reduced, then the size of defects or particles is reduced, but the polishing rate decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the slurry by incorporating specific organic additives and controlling pH levels (maintained between 2-10) to enhance the chemical reactivity of fine ceria particles (1-150 nm), enabling high polishing rates despite reduced particle size
Solution Approach 2:
The patent creates a composite slurry system combining inorganic ceria particles with organic additives (such as carboxylic acids, amines, or surfactants) to achieve both fine particle size for low defects and enhanced chemical-mechanical action for high polishing rates
2Productivity
If polishing accelerators are added, then the polishing rate is increased, but the dispersion stability is degraded
Solution Approach 1:
The patent introduces organic additives as intermediary substances that mediate between the ceria particles and the dispersion medium, providing steric or electrostatic stabilization to maintain dispersion stability while still enabling chemical reactivity for high polishing rates
Solution Approach 2:
The patent optimizes the pH parameter (maintained between 2-10) and the concentration of organic additives to simultaneously achieve stable dispersion and high polishing rate, avoiding the need for conventional polishing accelerators that compromise stability
3Productivity
If polishing accelerators are used, then the polishing rate is improved, but the process complexity increases due to material-specific adjustments
Solution Approach 1:
The patent develops a universal slurry formulation using ceria particles with surface modifications and pH control that can polish multiple materials (silicon oxide, tungsten, copper, etc.) with a single composition, eliminating the need for material-specific accelerator adjustments and simplifying the overall process
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 maintains high yield and productivity by increasing polishing rates for various layers, including silicon oxide, tungsten, and copper, while avoiding the need for oxidizers and ensuring environmental friendliness and economic efficiency.
Implementation Method 1
ceria particles having a NO3 functional group bonded to surfaces thereof
Implementation Method 2
a dispersion medium, and ceria particles
Implementation Method 3
A pH value of the slurry composition may range from 1 to 9. The slurry composition may further include a pH control agent.
Data Source
AI summary
A slurry composition for the CMP process includes a dispersion medium, and ceria particles having a NO3 functional group bonded to surfaces thereof. The ceria particles are contained in an amount of about 0.1 parts by weight to about 15 parts by weight based on 100 parts by weight of the dispersion medium.