EFEM Load Port Purging for Faster Inert Gas Exchange
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Solution Overview
Problem
Existing EFEMs face challenges in quickly replacing the atmosphere in the accommodation chamber with an inert gas, leading to prolonged startup times and particle contamination during the operation of the opening/closing mechanism, as the gas discharge unit is not connected to the accommodation chamber, allowing particles to enter the transfer chamber.
Innovation Solution
The EFEM design includes a gas discharge unit connected to the accommodation chamber of the load port, allowing for efficient inert gas replacement and particle discharge, with optional features like a fan in the accommodation chamber and a gas return path to enhance gas circulation and reduce particle contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gas discharge unit is connected to the lower portion of the gas return path (conventional configuration), then the EFEM can maintain nitrogen circulation in the transfer chamber, but the accommodation chamber is not included in the circulation flow path causing prolonged atmosphere replacement time and particle contamination
Solution Approach 1:
The gas discharge function is segmented into two separate discharge units: one connected to the gas return path for the transfer chamber, and another connected to the accommodation chamber. This segmentation allows independent and simultaneous atmosphere replacement in both chambers, resolving the contradiction by enabling the accommodation chamber to be purged without waiting for the main circulation cycle.
Solution Approach 2:
The accommodation chamber atmosphere is replaced in advance through the dedicated discharge unit before the opening/closing mechanism operates. This preliminary action ensures that particles are removed and inert gas atmosphere is established beforehand, preventing contamination during subsequent operations and reducing overall startup time.
2Object-affected harmful factors
If the gas discharge unit is connected to the lower portion of the gas return path (conventional configuration), then nitrogen circulation can be maintained, but particles in the accommodation chamber fly up during opening/closing mechanism operation and enter the transfer chamber
Solution Approach 1:
The gas discharge system is segmented into multiple independent discharge units positioned at different locations (gas return path and accommodation chamber). This segmentation allows targeted particle removal from the accommodation chamber without disrupting the main nitrogen circulation, effectively reducing particle contamination while maintaining manageable system complexity through modular design.
Solution Approach 2:
A dedicated gas discharge unit connected to the accommodation chamber acts as an intermediary mechanism that specifically addresses particle contamination in that chamber. This intermediary discharge path allows particles to be removed before they can enter the transfer chamber, solving the contamination problem without requiring complete system redesign.
3Productivity
If nitrogen is supplied and discharged through the circulation flow path only, then the transfer chamber atmosphere can be maintained, but the accommodation chamber atmosphere replacement is slow and inefficient
Solution Approach 1:
The nitrogen supply and discharge system is segmented into the main circulation flow path for the transfer chamber and a separate dedicated path for the accommodation chamber. This segmentation enables simultaneous and independent atmosphere replacement in both chambers, significantly improving overall productivity without requiring excessive nitrogen consumption, as each chamber is purged through its own optimized path.
Solution Approach 2:
The gas supply and discharge system is designed with multi-functionality to serve both the transfer chamber and accommodation chamber simultaneously. The inert gas supply unit can supply nitrogen to both chambers, and the dual discharge units can evacuate both chambers independently, making the system universally applicable to different chamber requirements and improving overall 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
This configuration enables rapid atmosphere replacement in both the transfer and accommodation chambers, reducing startup time and minimizing particle entry into the transfer chamber, while also optimizing inert gas consumption and cost through downward gas circulation.
Implementation Method 1
a circulation flow path configured to circulate nitrogen inside the housing and constituted of a transfer chamber and a gas return path
Implementation Method 2
with optional features like a fan in the accommodation chamber and a gas return path to enhance gas circulation
Data Source
AI summary
Particles in an accommodation chamber are also easily discharged while facilitating replacement of an atmosphere in the accommodation chamber with an inert gas. An EFEM includes a load port 4, a housing configured to define, in the housing, a transfer chamber closed by connecting the load port 4 to an opening provided in a partition wall, a supply pipe for supplying nitrogen to a transfer chamber, and a discharge pipe 49 for discharging a gas in the transfer chamber. The load port 4 includes an opening/closing mechanism 54 capable of opening and closing a lid 101 of a mounted FOUP 100, and an accommodation chamber 60 kept in communication with the transfer chamber via a slit 51b and configured to accommodate a part of the opening/closing mechanism 54. The discharge pipe 49 is connected to the accommodation chamber 60 to discharge the gas in the transfer chamber via the accommodation chamber 60.