Polishing Composition Amine Surfactant Trench Erosion
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Solution Overview
Problem
Current chemical-mechanical polishing compositions for silicon substrates, particularly for silicon oxide-containing substrates, face challenges in achieving high removal rates while maintaining planarization efficiency, often resulting in trench erosion and increased device defectivity due to rapid removal rates.
Innovation Solution
A chemical-mechanical polishing composition comprising wet-process ceria abrasive, a surfactant with an amine-containing anchor group and ethylene oxide-propylene oxide stabilizing group, an aromatic carboxylic acid or heteroaromatic carboxylic acid, and water, with a pH of 3 to 6, is used to polish substrates, providing improved removal rates and planarization efficiency by forming a protective layer in trenches and reducing TEOS erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blanket removal rate is increased to improve throughput, then productivity increases, but trench erosion and device defectivity increase
Solution Approach 1:
The polishing composition creates different polishing rates in different regions: fast polishing on planar surfaces (blanket oxide) and slow polishing in trench areas. This is achieved through the synergistic interaction of ceria abrasive, surfactant, and aromatic carboxylic acid that selectively modify the polishing behavior based on local surface topology, allowing high throughput while preventing trench erosion
Solution Approach 2:
The aromatic carboxylic acid acts as an intermediary chemical that mediates between the abrasive particles and the silicon oxide surface. It forms a complex with ceria that enhances polishing rate on planar surfaces while the surfactant protects trench regions, thus enabling high productivity without compromising device reliability
2Productivity
If the polishing rate is increased to reduce processing time, then productivity improves, but planarization efficiency deteriorates due to overpolishing
Solution Approach 1:
The polishing composition dynamically adapts its removal rate based on surface topography during the polishing process. As the surface transitions from pattern oxide to blanket oxide, the composition maintains optimal polishing rates through the synergistic action of ceria, surfactant, and aromatic carboxylic acid, achieving both high productivity and excellent planarization efficiency
Solution Approach 2:
The composition utilizes changes in chemical and physical parameters during polishing: the aromatic carboxylic acid modifies the chemical reactivity at different stages, while the surfactant adjusts the mechanical interaction between abrasive and surface. This dynamic parameter adjustment enables fast processing without sacrificing planarization precision
3Productivity
If a rapid removal rate composition is used to improve throughput, then productivity increases, but trench loss increases
Solution Approach 1:
The polishing composition exhibits spatially varying polishing characteristics: aggressive removal on exposed blanket oxide surfaces and gentle polishing in trench regions. The ceria-abrasive provides high removal rate where needed, while the surfactant-aromatic carboxylic acid combination protects trench areas from excessive material loss, resolving the contradiction between throughput and trench preservation
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 manageable step height removal with significantly diminished trench loss, enhancing planarization efficiency and stability over time, as demonstrated by examples with Jeffsperse and Solsperse surfactants, maintaining performance even after six weeks.
Implementation Method 1
a surfactant comprising an amine-containing anchor group and ethylene oxide-propylene oxide stabilizing group
Implementation Method 2
wet-process ceria abrasive
Data Source
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AI summary
The invention provides a chemical-mechanical polishing composition comprising (a) wet-process ceria abrasive, (b) a surfactant comprising an amine-containing anchor group and ethylene oxide-propylene oxide stabilizing group, wherein the surfactant has a molecular weight of from about 1000 Daltons to about 5000 Daltons, (c) an aromatic carboxylic acid or heteroaromatic carboxylic acid, and (d) water, wherein the polishing composition has a pH of about 3 to about 6. The invention further provides a method of chemically mechanically polishing a substrate with the inventive chemical-mechanical polishing composition. Typically, the substrates contain silicon oxide.