EFEM Door System Nitrogen Purge for Wafer Contamination
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Solution Overview
Problem
In the EFEM, atmospheric air and particles remain between the seal member, lid member, and door unit, leading to changes in wafer properties due to oxygen and moisture exposure, which contaminates the wafer conveyance chamber.
Innovation Solution
A door operation system with a first gas injection unit to inject nitrogen into the sealed space between the container and the door, and a first gas discharge unit to remove atmospheric air, ensuring cleanliness by eliminating oxygen, moisture, and particles before opening, while pressure adjusters control pressures to minimize gas flow and particle scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is used to seal between the base and the container, then sealing performance is improved, but atmospheric air and particles remain in the sealed space between the seal member, lid member, and door unit
Solution Approach 1:
The patent applies preliminary action by injecting inert gas into the sealed space before the door unit is opened. This preliminary gas injection displaces atmospheric air and particles from the sealed space between the seal member, lid member, and door unit, preventing contamination when the door is subsequently opened. The gas injection unit introduces inert gas through a nozzle into the sealed space, ensuring that harmful atmospheric components are removed before exposure occurs.
Solution Approach 2:
The patent employs an inert atmosphere by injecting inert gas (such as nitrogen) into the sealed space to replace atmospheric air. This creates an inert environment that prevents oxidation and contamination of wafers. The inert gas displaces oxygen and moisture from the sealed space between the seal member, lid member, and door unit, eliminating the harmful atmospheric conditions that would otherwise cause wafer degradation.
2Ease of operation
If the door unit is opened to transfer wafers, then wafer transfer is enabled, but atmospheric air enters the conveyance space causing contamination
Solution Approach 1:
The patent applies preliminary action by injecting inert gas into the sealed space before the door unit is opened. This preliminary gas injection displaces atmospheric air and particles from the sealed space between the seal member, lid member, and door unit, preventing contamination when the door is subsequently opened. The gas injection unit introduces inert gas through a nozzle into the sealed space, ensuring that harmful atmospheric components are removed before exposure occurs.
Solution Approach 2:
The patent employs an inert atmosphere by injecting inert gas (such as nitrogen) into the sealed space to replace atmospheric air. This creates an inert environment that prevents oxidation and contamination of wafers. The inert gas displaces oxygen and moisture from the sealed space between the seal member, lid member, and door unit, eliminating the harmful atmospheric conditions that would otherwise cause wafer degradation.
3Object-affected harmful factors
If gas is injected into the sealed space to remove atmospheric air, then cleanliness is improved, but device complexity increases due to additional gas injection and discharge units
Solution Approach 1:
The patent applies the taking out principle by extracting the gas injection and discharge functions from the main door unit structure. The gas injection unit and discharge unit are implemented as separate, modular components with nozzles positioned at strategic locations. This extraction allows the cleanliness function to be added without significantly complicating the core door mechanism, as the gas management system operates independently through dedicated injection and discharge pathways.
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
Effectively prevents atmospheric air and particles from entering the conveyance space, maintaining the cleanliness of the container and conveyance space by repeatedly injecting and discharging nitrogen, thus preventing oxidation and contamination of wafers.
Implementation Method 1
a first gas injection unit configured to inject a gas into the sealed space
Implementation Method 2
a first gas discharge unit configured to discharge a gas from the sealed space
Implementation Method 3
a first seal member for sealing between the base and the container; a second seal member for sealing between the base and the door
Data Source
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AI summary
Provided are a door opening/closing system which prevents the entry of atmospheric air into a front-opening unified pod (FOUP) and an equipment front end module (EFEM) when the FOUP and the EFEM are placed in communication with each other, and a load port equipped with the door opening/closing system. The door opening/dosing system is provided with: a base 41 which constitutes a part of a wall isolating a conveyance space from an external space; an opening portion 92 provided in the base 41; a door 81 which is capable of opening and closing the opening portion 92; a first seal member 94 which seals a gap between the base 41 and a container 7 ; a second seal member 96 which seals a gap between the base 41 and the door 81; a sealed space which is constituted by the base 41, the first seal member 94, the second seal member 96, a lid member 72, and the door 81 when the container 7 is in a state of contact with the opening portion 92 with the first seal member 94 therebetween; a first gas injection unit 87 which injects gas into the sealed space; and a second gas discharge unit 88 which evacuates the sealed space.