CMP Slurry Composition for Low Oxide Trench Dishing
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) compositions for Shallow Trench Isolation (STI) do not effectively reduce oxide trench dishing and maintain polishing window stability, leading to issues with electrical current leakage and transistor performance.
Innovation Solution
A CMP polishing composition comprising abrasive particles, such as ceria-coated silica, and chemical additives like maltotritol, which reduce oxide trench dishing and enhance selectivity between silicon dioxide and silicon nitride, while maintaining stable mean particle size and pH across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP compositions are used for STI polishing, then oxide film removal rate is achieved, but oxide trench dishing increases leading to poor isolation and device failure
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific organic compounds (polyols with multiple hydroxyl groups, carboxylic acids, amines, or halides) that alter the chemical interaction between abrasive particles and oxide material. This chemical modification enables selective removal of oxide while preserving trench walls, resolving the contradiction between removal rate and trench dishing control
Solution Approach 2:
The invention uses composite abrasive particles consisting of ceria core coated with silica shell, combining the high removal rate properties of ceria with the selective etching and trench protection properties of silica. This composite structure enables simultaneous achievement of high productivity and manufacturing precision by leveraging the complementary properties of different materials
2Productivity
If high oxide removal rate is pursued, then polishing efficiency improves, but selectivity between silicon dioxide and silicon nitride decreases
Solution Approach 1:
The patent adjusts the chemical parameters of the slurry by incorporating specific organic compounds that modify the chemical reactivity of abrasive particles toward different materials. The polyols, carboxylic acids, amines, or halides create a chemical environment that enhances the selectivity ratio between oxide removal and nitride removal, allowing high efficiency while maintaining reliability through controlled chemical interactions
3Productivity
If polymeric electrolytes with low molecular weight are used, then polishing activity is enhanced, but particle size stability and pH control deteriorate
Solution Approach 1:
The patent uses composite abrasive particles with ceria core and silica shell, where the silica coating provides structural stability and pH buffering capacity while the ceria core maintains high polishing activity. This composite structure resolves the contradiction by separating the functional roles: the core provides activity while the shell provides stability
Solution Approach 2:
The invention modifies the molecular weight parameter of polymeric electrolytes to higher ranges (10,000 to 1,000,000) compared to conventional low molecular weight polymers. This parameter change enhances particle size stability and pH control while maintaining adequate polishing activity, resolving the contradiction between productivity and composition stability
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 reduced oxide trench dishing, improved polishing window stability, high oxide film removal rates, low silicon nitride film removal rates, and high selectivity, along with reduced total defect counts and stable abrasive particle sizes, enhancing transistor performance and device yield.
Implementation Method 1
chemical mechanical polishing
Implementation Method 2
chemical mechanical polishing
Data Source
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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 unique chemical additives, such as maltitol, lactitol, maltotritol, ribitol, D-sorbitol, mannitol, dulcitol, iditol, D-(-)-Fructose, sorbitan, sucrose, ribose, Inositol, glucose, D-arabinose, L-arabinose, D-mannose, L-mannose, meso-erythritol, beta-lactose, arabinose, or combinations thereof as oxide trench dishing reducing additives.