CMP Slurry Reducing Oxide Trench Dishing via Composite Particles
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) processes for microelectronics fail to effectively reduce oxide trench dishing and maintain polishing window stability, leading to electrical issues and device failures due to non-uniform trench oxide loss.
Innovation Solution
A CMP composition comprising ceria-coated inorganic metal oxide particles, chemical additives with multiple hydroxyl functional groups, and a solvent, which reduces oxide trench dishing and enhances selectivity between silicon dioxide and silicon nitride, while maintaining stable mean particle size and low defect counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP processes are used to achieve high oxide removal rates, then oxide film removal rate is improved, but oxide trench dishing increases
Solution Approach 1:
The slurry contains non-polishing particles (200-2000 nm) that selectively accumulate in trench regions to reduce polishing in those areas, while abrasive particles (5-50 nm) maintain high polish rates at elevations. This local differentiation of particle functions resolves the contradiction between high removal rate and reduced dishing.
Solution Approach 2:
The slurry is a composite system containing both abrasive particles (ceria, alumina, silica, zirconia) and non-polishing particles (polymeric electrolyte salts), creating a multi-functional material that simultaneously achieves high removal rates and reduced trench dishing through the combined actions of different particle types.
2Productivity
If conventional CMP processes are used to increase polishing speed, then productivity is improved, but polishing window stability deteriorates
Solution Approach 1:
The non-polishing particles act as a feedback mechanism that automatically modulates polishing rate in trench regions based on local material presence, maintaining stable polishing windows by preventing over-polishing and reducing sensitivity to process parameter variations.
3Productivity
If high selectivity between silicon dioxide and silicon nitride is achieved, then oxide removal rate is improved, but trench oxide loss increases
Solution Approach 1:
The differential particle size distribution creates local quality variations where non-polishing particles preferentially occupy trench regions, reducing oxide loss there, while abrasive particles continue to provide high selectivity and removal rates in elevated areas.
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 solution achieves high oxide film removal rates, low silicon nitride film removal rates, high selectivity, and improved polishing window stability, significantly reducing oxide trench dishing and total defect counts, thus enhancing transistor performance and fabrication yields.
Implementation Method 1
abrasive particles selected from the group consisting of ceria-coated inorganic metal oxide particles
Implementation Method 2
chemical mechanical polishing (CMP) for polishing oxide
Implementation Method 3
chemical additives as oxide trenching dishing reducers
Data Source
AI summary
Chemical mechanical planarization (CMP) polishing compositions, methods and systems are provided to reduce oxide trench dishing and improve over-polishing window stability. High and tunable silicon oxide removal rates, low silicon nitride removal rates, and tunable SiO2:SiN selectivity are also provided. The compositions use a unique combination of abrasives such as ceria coated silica particles and chemical additives such as maltitol, lactitol, maltotritol or combinations as oxide trench dishing reducing additives.