Guanidinium Polyionic CMP Slurries for Low-Dishing Tungsten Planarization
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Solution Overview
Problem
Existing chemical mechanical planarization (CMP) slurries face challenges in controlling topological defects such as dishing and erosion of tungsten lines and metal arrays, which are critical for achieving planarity in semiconductor manufacturing, especially at the 7 nm node and beyond.
Innovation Solution
The use of guanidinium-based polyionic liquids as additives in CMP slurries, which are synthesized through methods like free radical polymerization or reversible addition-fragmentation chain-transfer polymerization, to enhance removal rates and selectivity while minimizing dishing and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP slurries are used for tungsten polishing, then polishing process can be maintained, but topological defects such as dishing and erosion of tungsten lines and metal arrays occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating polyionic liquids with specific ionic groups (carboxylate, sulfonate, phosphate, borate, or arsenate) at controlled concentrations (0.01-5 wt%). This chemical parameter change alters the interaction between slurry and tungsten surface, reducing topological defects like dishing and erosion while maintaining planarity.
Solution Approach 2:
The invention creates a composite slurry system by combining traditional CMP slurry components with polyionic liquid additives. This composite formulation integrates the mechanical abrasion capability of conventional slurries with the defect-reducing properties of polyionic liquids, achieving both material removal and surface quality improvement.
2Productivity
If high removal rates are achieved in tungsten CMP, then productivity increases, but dishing and erosion defects worsen
Solution Approach 1:
The patent adjusts chemical composition parameters by introducing polyionic liquids with specific ionic groups that modify the chemical interaction at the wafer-slurry interface. This enables tuning of the removal rate while simultaneously controlling topography, breaking the traditional trade-off between productivity and precision.
Solution Approach 2:
The polyionic liquid acts as a chemical intermediary between the abrasive particles and the tungsten surface. It modulates the chemical reaction and material removal process, enabling high removal rates while preventing excessive dishing and erosion through its ionic groups that interact with metal surfaces.
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
Guanidinium-based polymers effectively reduce dishing and erosion in tungsten CMP processes, maintaining desirable polishing rates and improving the planarity of semiconductor wafers.
Implementation Method 1
The slurry initiates the polishing process by chemically reacting with the film being polished
Implementation Method 2
Removal of tungsten in the CMP is believed to be due to synergy between mechanical abrasion and tungsten oxidation followed by dissolution
Implementation Method 3
Removal of tungsten in the CMP is believed to be due to synergy between mechanical abrasion and tungsten oxidation followed by dissolution
Data Source
AI summary
Synthesis of guanidinium-based polymers is disclosed. Chemical Mechanical Planarization (CMP) slurries comprise abrasives; activator; oxidizing agent; additive comprising guanidinium-based polymers; and water. The use of the synthesized guanidinium-based polymers in the CMP slurries reduces dishing and erosion in highly selective tungsten slurries.