Silane-Modified Ceria Nanoparticles for Stable CMP Removal
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Solution Overview
Problem
Existing polishing compositions using ceria abrasive particles face challenges in achieving desirable removal rates and particle size stability due to the potential blocking of active sites on the ceria particles during chemical-mechanical polishing.
Innovation Solution
A chemical-mechanical polishing composition is developed using ceria abrasive particles modified with silanes of Formula I, which are associated with surface atoms of the ceria particles, enhancing stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ceria abrasive particles are surface modified with silane, then particle size stability is improved, but removal rate decreases due to blocking of active sites
Solution Approach 1:
The patent changes the chemical parameters of the silane modification process, specifically using silanes with controlled molecular weight (1500 Daltons or less) and specific functional groups (Formula I with n=1,2,3 and specific R1 and X groups). This parameter optimization allows the silane to provide steric stabilization for particle size control while maintaining sufficient surface activity for effective material removal during CMP.
2Reliability
If ceria abrasive particles are surface modified, then colloidal stability is improved, but active sites are blocked resulting in reduced removal rates
Solution Approach 1:
The silane modification creates local quality differences on the ceria particle surface. The silane groups provide colloidal stability through steric hindrance and electrostatic repulsion, while the ceria surface maintains its chemical reactivity. This localized modification approach ensures that particle stabilization and chemical activity coexist without mutual interference.
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 achieves high removal rates and improved particle size stability, resulting in low substrate defectivity and effective polishing of substrates with materials like silicon oxide and silicon nitride.
Implementation Method 1
ceria abrasive particles comprising at least one associated silane comprising at least one moiety of Formula I... wherein each X is the same or different and is any oxygen containing substituent, wherein at least one X is associated with a surface atom of the ceria abrasive particle
Implementation Method 2
moving the polishing pad and the chemical mechanical polishing composition relative to the substrate to abrade at least a portion of the substrate to polish the substrate
Data Source
AI summary
The invention provides a chemical-mechanical polishing composition comprising (i) ceria abrasive particles, wherein each ceria abrasive particle comprises at least one associated silane comprising at least one moiety of Formula I: Si(R1)n(X)(4-n), wherein R1, X, and n are as defined herein, and (ii) water. The invention also provides a method of chemically-mechanically polishing a substrate, especially a silicon oxide and/or silicon nitride substrate, by contacting the substrate with the inventive chemical-mechanical polishing composition.