Wet Bench Scrubber Cooling and Demisting for Fine Particle Removal
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Solution Overview
Problem
Current wet-type local scrubbers in semiconductor manufacturing struggle to efficiently remove ammonium salt particulates, particularly those smaller than 1 um, leading to excessive emissions that violate environmental regulations and result in unnecessary resource wastage and tool downtime.
Innovation Solution
Incorporation of structured packing and a vortex tube into the scrubbing system, along with a structured demister, to enhance mass transfer and particulate removal, coupled with an inline sensor and adaptive control system to manage airflow and temperature for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional wet-type local scrubber is used, then the system structure is simple, but it fails to efficiently remove ammonium salt particulates smaller than 1 um, leading to excessive emissions
Solution Approach 1:
The scrubber system is divided into multiple functional sections: a first scrubbing section with packed bed for initial particulate removal, a second scrubbing section with different packing material for further removal, and a demisting section. This segmentation allows each section to target specific particle sizes and mechanisms, achieving high removal efficiency for sub-1um particulates while maintaining manageable system complexity through modular design
Solution Approach 2:
The patent introduces a demisting section as an intermediary component between the scrubbing sections and the exhaust outlet. This demisting section uses a demister pad as a mediator to capture fine particulates and liquid aerosols that escape the packed bed scrubbing sections, providing an additional removal mechanism without significantly increasing overall system complexity
2Productivity
If the scrubber operates without adaptive control, then the system operation is simple, but it results in unnecessary resource wastage and tool downtime due to insufficient particulate removal
Solution Approach 1:
The control system incorporates feedback mechanisms where sensors monitor particulate removal efficiency and operational parameters in real-time. This feedback is used by the controller to dynamically adjust operating conditions such as liquid flow rates and airflow, ensuring optimal particulate removal performance and preventing tool downtime while avoiding unnecessary resource consumption through adaptive rather than static operation
Solution Approach 2:
The system transitions from static operation to dynamic adaptive control where operating parameters are continuously adjusted based on real-time conditions. The controller modifies liquid flow rates, airflow rates, and other operational variables dynamically to match actual particulate loading and removal efficiency requirements, improving productivity while maintaining reasonable automation complexity
3Object-affected harmful factors
If higher liquid flow rate is used to improve particulate removal, then particulate removal efficiency increases, but energy consumption and resource wastage increase
Solution Approach 1:
Instead of using high liquid flow rates throughout the entire system, the patent applies liquid flow selectively and partially in each scrubbing section. The first and second scrubbing sections use different liquid flow rates optimized for their specific removal targets, avoiding excessive liquid consumption while achieving high particulate removal efficiency. The demisting section uses minimal liquid for its specific function of capturing fine aerosols
Solution Approach 2:
The system optimizes liquid flow rates as a variable parameter for each scrubbing section rather than using a uniform high flow rate. By changing and optimizing the liquid flow parameter independently in each section based on its specific removal efficiency requirements, the system achieves high particulate removal while minimizing overall liquid and energy consumption through parameter optimization rather than excessive action
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 system achieves enhanced removal of ammonium salt particulates, reducing emissions to below regulatory limits, minimizing tool downtime, and optimizing resource utilization.
Implementation Method 1
a vortex tube, configured to cool the second scrubbing chamber
Implementation Method 2
a structured packing material, configured to remove a first portion of the particulates from the exhaust
Implementation Method 3
a structured demister, configured to remove a second portion of the particulates from the exhaust
Data Source
AI summary
A method includes: processing a wafer by a wet bench apparatus; forming particulates in an exhaust of the wet bench apparatus; flowing the exhaust to a first scrubbing chamber of a scrubber; removing a first portion of the particulates from the exhaust by flowing the exhaust to a second scrubbing chamber via a structured packing material; cooling the second scrubbing chamber by a vortex tube; and removing a second portion of the particulates from the exhaust by a structured demister adjacent the second scrubbing chamber.