CMP Slurry Composition for Fast Mo/W Polishing With Low Etching
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) processes for semiconductor manufacturing face challenges in achieving high polishing rates for molybdenum and tungsten while minimizing etching and requiring multiple steps, which complicates the process and reduces efficiency.
Innovation Solution
A slurry composition for chemical mechanical metal polishing is developed, comprising a corrosion inhibitor with specific aliphatic or aromatic heterocyclic compounds, abrasive particles, an oxidizing agent, and a solvent. This composition enhances the polishing rate and selectivity ratio for molybdenum and tungsten relative to silicon nitride, while reducing etching and allowing for continuous polishing without stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP slurry is used for molybdenum/tungsten polishing, then polishing can be performed, but the polishing rate is low and etching occurs simultaneously
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by introducing specific heterocyclic compounds (pyridine, pyrimidine, triazine, tetrazole, imidazole, or oxazole rings) with controlled concentrations (0.01-10 wt%). These parameter changes alter the chemical reactivity of the slurry, enabling selective removal of molybdenum/tungsten through chemical reaction while suppressing unwanted etching effects, thus resolving the contradiction between achieving high polishing rate and minimizing etching.
Solution Approach 2:
The patent creates a composite slurry system combining traditional abrasive particles (silica, alumina, or ceria) with organic heterocyclic compounds. This composite formulation integrates mechanical abrasion capabilities with selective chemical etching properties, allowing the slurry to simultaneously achieve high polishing rate through mechanical action and selective removal through chemical reaction, while minimizing harmful etching of non-target materials.
2Manufacturing precision
If multiple polishing steps are used to achieve planarization, then polishing precision can be improved, but process complexity increases
Solution Approach 1:
The patent develops a universal CMP slurry composition that can effectively polish multiple materials (molybdenum, tungsten, and other metals) with a single formulation. The heterocyclic compounds in the slurry provide broad-spectrum chemical reactivity that works across different metal types, allowing a single polishing step to achieve planarization of multi-layer metal structures without requiring material-specific polishing steps, thus reducing process complexity while maintaining precision.
Solution Approach 2:
The patent enables continuous polishing action by formulating a slurry that maintains effective chemical reactivity and mechanical abrasion throughout the polishing process. The heterocyclic compounds continuously react with metal surfaces during polishing, preventing passivation and maintaining high removal rates throughout the entire polishing cycle, allowing single-step continuous polishing to achieve the same planarization quality that previously required multiple interrupted steps.
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 solution significantly increases the polishing rate of molybdenum and tungsten, improves selectivity over silicon nitride, and reduces etching, thereby simplifying the CMP process and enhancing semiconductor manufacturing efficiency.
Implementation Method 1
chemically reacting the chemical components included in the slurry composition with the surface of the semiconductor substrate
Implementation Method 2
mechanically polishing by mechanically rubbing the surface protrusions of the polishing pad and the abrasive included in the polishing slurry with the surface of the semiconductor substrate
Implementation Method 3
simultaneously chemically removing the surface of the semiconductor substrate by chemically reacting the chemical components included in the slurry composition
Data Source
AI summary
A slurry composition for chemical mechanical metal polishing includes a corrosion inhibitor, abrasive particles, an oxidizing agent, and a solvent. The corrosion inhibitor includes a C2 to C30 aliphatic heterocyclic compound including at least one nitrogen atom in the ring and at least one functional group selected from a halogen, an amine group, a cyclic amine group, a nitro group, an amide group, a carboxyl group, a hydroxy group, a thiol group, an alkoxy group, a C10 to C30 alkyl group, or an ester group; or a C2 to C30 aromatic heterocyclic compound including at least one nitrogen atom in the ring and at least one functional group selected from a halogen, an amine group, a cyclic amine group, a nitro group, an amide group, a carboxyl group, a hydroxy group, a thiol group, an alkoxy group, a C10 to C30 alkyl group, and an ester group; or a combination thereof.