CMP Slurry Selective Oxide Nitride Polishing
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Solution Overview
Problem
Conventional chemical-mechanical polishing compositions for semiconductor substrates often result in overpolishing and topographical defects like dishing, which can lead to short-circuits and device performance issues due to inadequate selectivity and high defectivity during shallow trench isolation processes.
Innovation Solution
A chemical-mechanical polishing composition comprising ceria abrasive, specific nonionic polymers, picolinic acid, and pH-adjusting compounds, which provides selective removal rates for silicon oxide, silicon nitride, and polysilicon with low particle defectivity and suitable dishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing compositions are used to achieve high removal rates for silicon oxide, then productivity is improved, but manufacturing precision deteriorates due to overpolishing and dishing defects
Solution Approach 1:
The polishing composition uses ceria abrasive particles with controlled size distribution (0.1-10 micrometers) and specific surface area (5-50 m²/g), combined with pH buffering (pH 7-9) and specific additive concentrations, to achieve optimal balance between removal rate and surface uniformity, preventing both overpolishing and dishing defects
Solution Approach 2:
The composition combines ceria abrasive particles with a complex formulation including nonionic surfactants, polymers, chelating agents, and pH buffers to create a composite polishing slurry that provides both high removal rate and excellent surface uniformity, resolving the contradiction between productivity and manufacturing precision
2Manufacturing precision
If conventional polishing compositions are used to increase selectivity for oxide over silicon nitride, then manufacturing precision is improved, but productivity deteriorates due to decreased removal rate on silicon nitride
Solution Approach 1:
The composition achieves enhanced selectivity through specific parameter optimization: ceria particle size distribution (0.1-10 micrometers), pH buffering (pH 7-9), and controlled concentrations of nonionic surfactants and polymers, which together provide differential polishing rates between oxide and silicon nitride while maintaining high overall productivity
3Productivity
If conventional polishing compositions are used to achieve high removal rates, then productivity is improved, but manufacturing precision deteriorates due to increased defectivity
Solution Approach 1:
The composition controls defectivity through optimized ceria particle size (0.1-10 micrometers with specific surface area 5-50 m²/g), pH buffering (pH 7-9), and additive packages including nonionic surfactants and polymers, achieving high removal rates while minimizing particle defects and surface irregularities
Solution Approach 2:
Nonionic surfactants and polymers act as intermediaries between the ceria abrasive particles and the substrate surface, controlling the interaction to achieve high removal rates while preventing excessive mechanical stress and defect formation
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 high removal rates for silicon oxide while maintaining low removal rates for silicon nitride and polysilicon, reducing defects and dishing, thereby enhancing semiconductor device fabrication quality and performance.
Implementation Method 1
a ceria abrasive
Implementation Method 2
one or more nonionic polymers
Implementation Method 3
picolinic acid, and pH-adjusting compounds
Data Source
AI summary
The invention provides a chemical -mechanical polishing composition containing a ceria abrasive, one or more nonionic polymers, optionally one or more phosphonic acids, optionally one or more nitrogen-containing zwitterionic compounds, optionally one or more sulfonic acid copolymers, optionally one or mote anionic copolymers, optionally one or more polymers comprising quaternary amines, optionally one or more compounds that adjust the pH of the -polishing compositions, water, and optionally one or more additives. The invention further provides a method of chemically-mechanically polishing a substrate with the inventive chemical-mechanical polishing composition. Typically, the substrate contains silicon oxide, silicon nitride, and/or polysilicon.