Polishing Pad High Temperature Stability
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Solution Overview
Problem
Conventional polishing pads used in chemical mechanical polishing (CMP) processes for semiconductor manufacturing suffer from poor local planarization performance and increased defectivity due to softening at high temperatures, leading to unstable material properties over a wide temperature range.
Innovation Solution
The development of polishing pads with segmented polishing elements formed from a pre-polymer composition that maintains a storage modulus of 200 MPa or greater at 80°C, incorporating isobornyl acrylate, 3,3,5-Trimethylcyclohexyl acrylate, difunctional aliphatic urethane methacrylate, and difunctional aliphatic urethane acrylate oligomer, which provides consistent material properties and stable performance across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polishing pads are formed of harder materials to provide superior local planarization performance, then planarization performance is improved, but defectivity increases with undesirable scratches in substrate surface
Solution Approach 1:
The patent applies parameter changes by carefully controlling the glass transition temperature (Tg) of the polishing pad material to be above 80°C and adjusting the storage modulus to achieve optimal hardness. This allows the material to maintain sufficient hardness for good planarization performance while avoiding excessive hardness that would cause substrate scratches and defectivity.
2Object-affected harmful factors
If polishing pads are formed of softer materials to reduce defectivity and substrate scratches, then defectivity is reduced, but local planarization performance deteriorates
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the material parameters, specifically setting the storage modulus and glass transition temperature within optimal ranges. The material is engineered to have sufficient softness to minimize substrate damage while maintaining enough hardness through controlled Tg (>80°C) to achieve adequate local planarization performance.
3Duration of action of moving object
If conventional polishing pads are used at high temperatures, then polishing process can be maintained, but material properties become unstable with softening leading to poor performance
Solution Approach 1:
The patent addresses high temperature instability by changing the fundamental material parameter of glass transition temperature to be above 80°C. This ensures the polishing pad material remains stable and maintains its mechanical properties at elevated operating temperatures, preventing softening and performance degradation during the polishing process.
4Stability of the object's composition
If polishing pads maintain high storage modulus at elevated temperatures to ensure stable performance, then performance stability is improved, but material formulation complexity increases
Solution Approach 1:
The patent employs composite material formulation by combining multiple polymer components including polyurethane acrylate oligomers, isobornyl acrylate, and other monomers in specific ratios. This composite approach enables the material to achieve and maintain high storage modulus at elevated temperatures while providing the necessary mechanical and chemical properties for effective 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
These polishing pads demonstrate reduced dishing and erosion over a wide range of feature sizes, maintaining consistent polishing performance and reducing non-uniformity compared to conventional pads, while maintaining high storage modulus values even at elevated temperatures.
Implementation Method 1
A sample of the cured pre-polymer composition has a glass transition temperature (Tg) of about 80° C. or greater
Data Source
AI summary
Embodiments herein generally relate to polishing pads and methods of forming polishing pads. A polishing pad includes a plurality of polishing elements. Each polishing element comprises an individual surface that forms a portion of a polishing surface of the polishing pad and one or more sidewalls extending downwardly from the individual surface to define a plurality of channels disposed between the polishing elements. Each of the polishing elements has a plurality of pore-features formed therein. Each of the polishing elements is formed of a pre-polymer composition and a sacrificial material composition. In some cases, a sample of the cured pre-polymer composition has a glass transition temperature (Tg) of about 80° C. or greater. A storage modulus (E′) of the cured pre-polymer composition at a temperature of 80° C. (E′80) can be about 200 MPa or greater.