CMP Slurry Composition for Selective Oxide Polishing
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Solution Overview
Problem
Existing CMP slurry compositions struggle to simultaneously polish silicon oxide, silicon nitride, and polysilicon films with high selectivity, leading to defects like scratches and reduced throughput due to the need for frequent slurry changes.
Innovation Solution
A CMP slurry composition using high-purity colloidal silica as an abrasive, combined with polyethylene glycol and heterocyclic compounds as additives, allows for on-site adjustment of polishing selectivity among the three films, minimizing scratches and enabling efficient polishing of multiple films simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP slurry compositions are used to polish silicon oxide films, then polishing can be performed, but scratches and surface defects occur due to metal impurities in the abrasive
Solution Approach 1:
The patent uses colloidal silica abrasive particles that are designed to be consumed during polishing. The slurry is continuously supplied and the abrasive particles are replaced rather than reused, ensuring fresh abrasive without accumulated impurities that cause scratches.
Solution Approach 2:
The patent changes the chemical composition parameters of the slurry by using high-purity colloidal silica with controlled metal impurity levels and combining it with specific chemicals (ammonium fluoride, hydrogen peroxide) to achieve both high polishing rate and low scratch generation.
2Reliability
If frequent slurry changes are made to maintain polishing quality, then surface defects are minimized, but manufacturing throughput decreases
Solution Approach 1:
The patent develops a universal slurry composition that can effectively polish multiple film types (silicon oxide, silicon nitride, polysilicon) with different properties using the same slurry formulation, eliminating the need for frequent slurry changes while maintaining surface quality.
Solution Approach 2:
The patent enables continuous polishing operation by formulating a slurry that maintains its effectiveness throughout the polishing process without requiring interruption for changes, achieving continuous useful action in film removal while preserving surface quality.
3Manufacturing precision
If high selectivity slurry is used to polish one film type, then polishing precision is improved, but the ability to polish multiple films simultaneously deteriorates
Solution Approach 1:
The patent achieves high selectivity for silicon oxide polishing by optimizing specific parameters including pH (3-5), abrasive particle size (10-100 nm), and chemical concentrations, while the slurry formulation maintains adaptability to polish other films at controlled rates.
Solution Approach 2:
The patent uses a composite slurry system combining colloidal silica abrasive with multiple chemical components (ammonium fluoride, hydrogen peroxide, surfactants) that work synergistically to provide both high selectivity for silicon oxide and versatility for polishing multiple film types.
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 proposed CMP slurry composition improves polishing performance for silicon oxide films, minimizes surface defects, and enhances manufacturing efficiency by allowing continuous polishing without the need for frequent slurry changes.
Implementation Method 1
a polishing target material can be mechanically removed due to the friction between abrasive particles contained in the slurry and protrusions formed on the surface of the polishing pad
Implementation Method 2
a polishing target material can be chemically removed due to a chemical reaction of a chemical component contained in the slurry
Implementation Method 3
To achieve a high polishing rate for a silicon oxide film according to the electrostatic attraction theory, an abrasive material having a positive zeta potential that is opposite to the zeta potential of the silicon oxide film is used to increase the adsorption force with respect to the silicon oxide film
Data Source
AI summary
Proposed are a CMP slurry composition and a polishing method using the same. The CMP slurry composition in which the zeta potential of colloidal silica serving as an abrasive is properly controlled and metal impurities are removed from the colloidal silica and to a polishing method using the same. The CMP slurry composition is configured to improve a polishing performance for a silicon oxide film, minimize scratches on a finished surface, and to enable adjustment of a content ratio of an abrasive and an additive in the composition, thereby enabling adjustment of a polishing selectivity among a silicon oxide film, a silicon nitride film, and a polysilicon film.