EFEM Gas Circulation Reduces Nitrogen Consumption
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Solution Overview
Problem
The existing EFEM systems face challenges in maintaining a clean and inert atmosphere during wafer transportation, leading to potential corrosion and oxidation, while also incurring high nitrogen consumption and costs due to continuous nitrogen supply to prevent external air exposure.
Innovation Solution
An EFEM design with a housing that includes a wafer transport chamber with a gas delivery port, a gas suction port, and a feedback path, utilizing a downward gasflow and filtration to circulate and purify the gas, maintaining a closed environment and reducing nitrogen consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous nitrogen supply is used to prevent air exposure during wafer transport, then wafer surface integrity is maintained, but nitrogen consumption and cost increase
Solution Approach 1:
The patent recycles nitrogen gas by circulating it through a purification system that removes contaminants and moisture, then returns the cleaned nitrogen to the transport chamber. This closed-loop system recovers and reuses nitrogen instead of continuously supplying fresh nitrogen, reducing consumption while maintaining wafer surface integrity
Solution Approach 2:
The patent maintains an inert nitrogen atmosphere within the transport chamber to prevent oxidation and corrosion of wafer surfaces. By continuously circulating and purifying this inert gas rather than replacing it, the system preserves the protective atmosphere while reducing nitrogen usage
2Object-affected harmful factors
If nitrogen is supplied to pressurize FOUP interior to prevent air entry, then contamination is prevented, but nitrogen flow increases and cost rises
Solution Approach 1:
The patent captures nitrogen gas that would otherwise escape from the FOUP during wafer transfer operations, redirects it through a purification system, and recycles it back to the FOUP. This recovery process maintains the positive pressure and contamination barrier while significantly reducing the net nitrogen flow required
Solution Approach 2:
The patent implements a feedback mechanism where nitrogen gas flowing out of the FOUP is detected, captured, and fed back into the FOUP after purification. This closed-loop feedback system maintains the protective atmosphere and pressure differential while minimizing nitrogen loss
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 configuration effectively prevents particle adhesion and corrosion, maintains the wafer surface integrity, and reduces nitrogen usage and costs by circulating and purifying the gas within the EFEM system.
Implementation Method 1
a filter that is provided in the gas delivery port, and eliminates particles included in the gas to be delivered
Implementation Method 2
a gas feedback path that feedbacks gas sucked through the gas suction port to the gas delivery port; wherein the gas in the wafer transport chamber is circulated by generating a downward gasflow in the wafer transport chamber and feeding back the gas through the gas feedback path
Data Source
AI summary
An EFEM includes a housing 3 that constitutes a wafer transport chamber 9 that is substantially closed by connecting load ports 4 to an opening 31a provided on a wall 31, and connecting a processing apparatus 6; a wafer transport apparatus 2, and transports a wafer between the processing apparatus 6 and the FOUPs 7 mounted on the load ports 4; a gas delivery port 11; a gas suction port 12; a gas feedback path 10; and a FFU 13 that includes a filter 13b that is provided in the gas delivery port 11, and eliminates particles contained in the delivered gas, wherein the gas in the wafer transport chamber 9 is circulated by generating a downward gasflow in the wafer transport chamber 9 and feeding back the gas through the gas feedback path 10.