CMP Slurry Recirculation With Filtration for Stable Removal Rates
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Solution Overview
Problem
In chemical mechanical planarization (CMP) systems, the high cost and limited availability of complex slurry chemistries pose challenges, as these chemistries are expensive and wasteful if not reclaimed and reused effectively.
Innovation Solution
A CMP system with an integrated slurry recirculation system that captures used slurry, filters it, and returns it to the slurry delivery system, incorporating a metrology controller to adjust the slurry composition based on removal rate and properties measured by sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slurry is continuously delivered to the polishing platen, then the CMP process can maintain consistent removal rates, but the cost and waste increase due to limited availability and high cost of complex slurry chemistries
Solution Approach 1:
The patent implements a slurry recirculation system that captures used slurry from the polishing platen, filters it through coarse and fine filtration systems, and returns the recovered slurry back to the slurry delivery system. This recovery process reduces slurry chemistry waste while maintaining consistent removal rates by ensuring continuous availability of filtered slurry.
Solution Approach 2:
The recirculation system maintains continuous operation by constantly circulating and filtering slurry, ensuring that the polishing process always has access to fresh, filtered slurry without interruption. The system includes continuous filtration and recirculation pathways that prevent downtime and maintain consistent removal rates.
2Loss of substance
If a slurry recirculation system is implemented to capture and filter used slurry, then slurry waste is reduced and cost-effectiveness improves, but the device complexity increases
Solution Approach 1:
The recirculation system is divided into distinct functional segments: a capture system that collects used slurry from the polishing platen, a filtration system with separate coarse and fine filtration stages, and a recirculation pathway that returns filtered slurry to the delivery system. This segmentation allows each component to perform its specific function efficiently while simplifying the overall system design and maintenance.
3Device complexity
If captured slurry is directly returned to the slurry delivery system without filtration, then the system complexity is reduced, but the manufacturing precision deteriorates due to contamination from used slurry
Solution Approach 1:
The patent introduces a filtration system as an intermediary between the slurry capture and recirculation stages. The filtration system includes coarse filtration to remove large particles and fine filtration to remove smaller contaminants, ensuring that only clean, filtered slurry is returned to the delivery system. This intermediary filtration process prevents contamination while maintaining system 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 slurry recirculation system reduces waste and conserves expensive slurry chemistries by effectively reusing filtered slurry, while maintaining consistent removal rates and improving the overall efficiency and cost-effectiveness of the CMP process.
Implementation Method 1
a coarse filtration filter configured to perform a first filtration of the captured slurry
Implementation Method 2
a fine filtration filter configured to receive the captured slurry from the coarse filtration filter and perform a second filtration of the captured slurry
Data Source
AI summary
An apparatus and method for in-situ chemical separation and recirculation in a chemical mechanical processing system are provided. In one aspect, a chemical mechanical planarization system includes a polishing platen having a surface configured to polish a substrate and a slurry delivery system configured to deliver slurry to the surface of the polishing platen. The apparatus can further include an effluent capture apparatus configured to capture the slurry from the polishing platen, filter the captured slurry, and provide the filtered slurry to the slurry delivery system.