Core-Shell Silica Particles for Selective CMP Removal Control
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Solution Overview
Problem
Existing silica particles used in chemical-mechanical polishing (CMP) for semiconductor manufacturing suffer from high aluminum loss, making it difficult to maintain a specific charge and concentration, which affects the selectivity and efficiency of removing conductive and dielectric materials.
Innovation Solution
The development of core-shell silica particles with an aluminate-comprising shell, produced by reacting silicic acid and sodium aluminate under alkaline conditions, followed by cation exchange resin treatment, to achieve a controlled negative charge and improved selectivity in CMP processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica particles are surface-modified with aluminate ions to achieve negative charge, then the particles can be used for CMP of conductive materials, but aluminum is lost from the surface making it difficult to maintain specific charge and concentration
Solution Approach 1:
The patent applies composite materials by creating core-shell silica particles where the core provides structural stability and the shell contains aluminate ions. This composite structure prevents aluminum loss while maintaining the negative charge necessary for CMP performance on conductive materials.
Solution Approach 2:
The patent applies local quality by concentrating aluminate ions specifically in the shell region of the silica particles rather than uniformly distributing them throughout. This localized placement in the shell protects the aluminum from loss while maintaining the necessary charge at the particle surface for effective CMP.
2Reliability
If high aluminum content is used to achieve sufficient negative charge, then particle performance on conductive materials improves, but selectivity between conductive and dielectric materials deteriorates
Solution Approach 1:
The patent applies local quality by placing aluminate ions specifically in the shell region rather than uniformly throughout the particle. This localized concentration achieves the necessary negative charge for good conductive material performance while the controlled distribution maintains selectivity against dielectric materials.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the aluminum concentration and distribution in the shell region. By adjusting the aluminate content and its spatial distribution, the patent optimizes both particle performance on conductive materials and selectivity against dielectric materials simultaneously.
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 core-shell silica particles provide enhanced selectivity and control over removal rates between conductive and dielectric materials, ensuring efficient planarization in semiconductor manufacturing.
Implementation Method 1
reacting silicic acid and sodium aluminate under alkaline conditions, to form a shell onto said silica particles
Implementation Method 2
followed by cation exchange resin treatment, to achieve a controlled negative charge
Data Source
AI summary
The present application relates to negatively charged silica particles, to a method of producing such particles, and to compositions comprising such particles as well as to a method for chemical mechanical polishing.