CMP Slurry Suppressing Amorphous Silicon Removal
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Solution Overview
Problem
In semiconductor processing, chemical mechanical polishing (CMP) techniques face challenges in achieving a balanced removal rate of amorphous silicon while maintaining tunable oxide to silicon nitride ratios, which is crucial for planarizing substrates in advanced semiconductor devices.
Innovation Solution
The use of chemical mechanical polishing compositions containing colloidal silica abrasive particles with a positive zeta potential, phosphoric acid or its salts, and polyethoxylated amine compounds, specifically formulated to suppress the removal rate of amorphous silicon while allowing for tunable oxide to silicon nitride removal rate ratios, is employed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP compositions are used to achieve high oxide removal rate, then oxide planarization is improved, but amorphous silicon removal rate increases excessively causing dishing and loss of control
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating phosphoric acid and polyethoxylated amine compounds in specific concentrations. These parameter changes alter the chemical reactivity toward different materials, enabling selective suppression of silicon removal while maintaining oxide removal rates, thus resolving the contradiction between productivity and precision.
Solution Approach 2:
The invention uses a composite polishing composition containing multiple components including colloidal silica abrasives, phosphoric acid, polyethoxylated amines, and other additives. This composite formulation creates synergistic effects where the combination of chemicals provides selective removal characteristics that individual components cannot achieve alone, allowing simultaneous control of oxide and silicon removal rates.
2Productivity
If aggressive polishing conditions are used to increase removal rate, then planarization speed is improved, but surface quality deteriorates due to increased roughness and defects
Solution Approach 1:
The invention modifies chemical parameters in the polishing composition, including pH control through phosphoric acid and surfactant concentrations, to enable effective polishing at reduced mechanical aggression. This allows maintaining high removal rates while minimizing surface damage, roughness, and defect formation that typically accompany aggressive mechanical polishing.
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
This approach effectively suppresses the removal rate of amorphous silicon while maintaining high selectivity and tunable ratios of silicon nitride to oxide, enhancing the planarization process in semiconductor manufacturing.
Implementation Method 1
the wafer surface is polished and made planar by the chemical and mechanical action of the pad surface and slurry
Implementation Method 2
a chemical mechanical polishing composition, comprising, as initial components: water; colloidal silica abrasive particles comprising nitrogen containing compounds and a positive zeta potential; phosphoric acid or salt thereof
Implementation Method 3
phosphoric acid or salt thereof; a polyethoxylated amine compound having formula (I)
Data Source
AI summary
Chemical mechanical polishing compositions contain polyethoxylated amines, phosphoric acid or salts thereof, and positively charged nitrogen containing colloidal silica abrasive particles. The chemical mechanical polishing compositions are used in polishing methods for suppressing the removal rate of amorphous silicon while maintaining tunable oxide to silicon nitride removal rate ratios. The chemical mechanical polishing compositions can be used in front-end-of line semiconductor processing.