Ceria Polishing Composition for STI Planarization
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving high removal rates of silicon oxide patterns during shallow trench isolation (STI) processes while maintaining planarization efficiency to prevent trench erosion and device defectivity.
Innovation Solution
A chemical-mechanical polishing composition comprising wet-process ceria particles with a median particle size of 25 nm to 150 nm and a particle size distribution of 300 nm or more, optimized with tridentate hydroxyl groups on their surface, is used in conjunction with an aqueous carrier to enhance polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing compositions (slurries or creams) are used, then polishing capability is achieved, but control over polishing parameters (particle size, shape, composition) is poor
Solution Approach 1:
The patent applies parameter changes by precisely controlling particle size (0.1-10.0 μm), shape (spherical, cubic, irregular), and composition (ceria content 1-50 wt%) of the polishing particles to achieve optimal polishing performance for different semiconductor substrates, thereby improving manufacturing precision while maintaining formulation simplicity
Solution Approach 2:
The patent uses composite polishing compositions containing ceria particles combined with specific binders (polymer binders, colloidal silica, or organic vehicles) to enhance both polishing capability and control over polishing parameters, resolving the contradiction between performance and formulation complexity
2Manufacturing precision
If CMP polishing is used to achieve planarization, then surface flatness is improved, but dishing defects occur on wafers
Solution Approach 1:
The patent applies local quality by using spherical ceria particles with controlled size distribution (0.1-10.0 μm) that provide uniform polishing pressure distribution across the wafer surface, achieving planarization while minimizing dishing defects through optimized local polishing characteristics
Solution Approach 2:
The patent changes the particle shape parameter to spherical morphology and controls particle size within 0.1-10.0 μm range, which reduces stress concentration and prevents excessive material removal from center regions, thereby eliminating dishing while maintaining surface flatness
3Productivity
If mechanical polishing is used to remove material, then material removal rate is achieved, but surface defects are generated
Solution Approach 1:
The patent partially replaces aggressive mechanical polishing with chemically-assisted mechanical polishing (CAMAP) using ceria particles that combine chemical reaction with mechanical removal, achieving high material removal rates while producing defect-free surfaces through the synergistic chemical-mechanical action
Solution Approach 2:
The patent uses composite polishing systems combining ceria particles with chemical agents in the slurry formulation, enabling simultaneous chemical etching and mechanical removal that increases productivity while eliminating surface defects through the combined action mechanism
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 composition achieves higher removal rates and improved planarization efficiency, reducing material removal while minimizing trench erosion, thereby increasing device throughput and reducing defectivity.
Implementation Method 1
Polishing compositions and methods employing ceria particles are provided. The ceria particles can be used in a slurry or cream for polishing a substrate
Implementation Method 2
The ceria particles can be used with a pad, with or without ultrasonic vibration
Data Source
AI summary
The invention provides a chemical-mechanical polishing composition including wet-process ceria particles having a median particle size of about 25 nm to about 150 nm and a particle size distribution of about 300 nm or more, and an aqueous carrier. The invention also provides a method of polishing a substrate, especially a substrate comprising a silicon layer, with the polishing composition.