CMP Slurry Additive Stabilizes Silica Abrasive
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Solution Overview
Problem
Conventional chemical mechanical polishing compositions for dielectric layers in semiconductor fabrication face challenges in achieving low defectivity and tailored silicon oxide removal rates, especially as device sizes shrink, leading to unacceptable scratches that limit yield.
Innovation Solution
A chemical mechanical polishing composition comprising water, colloidal silica abrasive, and a specific additive according to formula I, which stabilizes the abrasive and minimizes agglomeration while maintaining silicon oxide removal rates and significantly reducing defects, such as scratches, by using a pH of ≥10 and minimal inclusion compounds and oxidizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP compositions are used to achieve high silicon oxide removal rates, then productivity is improved, but manufacturing precision deteriorates due to increased defectivity and scratches
Solution Approach 1:
The patent changes the chemical composition parameters of the CMP slurry by incorporating specific additives (formula I compounds) and adjusting pH to ≥10, which modifies the interaction between abrasive particles and silicon oxide, enabling high removal rates with reduced defect generation
Solution Approach 2:
The patent uses a composite slurry formulation combining colloidal silica abrasive with organic additives (formula I compounds containing nitrogen, sulfur, or phosphorus), creating a synergistic system that achieves both high productivity and low defectivity through combined mechanical and chemical effects
2Productivity
If polishing pressure is increased to improve planarization speed, then productivity is improved, but object-generated harmful factors worsen due to increased scratches and defects
Solution Approach 1:
The patent introduces chemical additives (formula I compounds) as intermediaries that mediate between the mechanical polishing action and the silicon oxide surface, facilitating material removal through chemical assistance while reducing direct mechanical damage that causes scratches
Solution Approach 2:
The patent partially replaces mechanical removal with chemical action by using pH-adjusted slurry and reactive additives, reducing reliance on high mechanical pressure and thereby decreasing scratch formation while maintaining planarization efficiency
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 a silicon oxide removal rate of ≥1,000 Å/min with a reduced defect count, specifically ≤25 scratches larger than 0.16 μm, enhancing polishing defectivity performance and maintaining silicon oxide removal rates substantially unchanged.
Implementation Method 1
a colloidal silica abrasive
Implementation Method 2
Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize substrates
Implementation Method 3
an additive according to formula I... which stabilizes the abrasive and minimizes agglomeration
Data Source
AI summary
A low defect chemical mechanical polishing composition for polishing silicon oxide containing substrates is provided comprising, as initial components: water, a colloidal silica abrasive; and, an additive according to formula I.