EFEM Return Path Electrostatic Capture for Particle Leak Control
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Solution Overview
Problem
In EFEMs that circulate gas, differential pressure between the return path and the transfer chamber can lead to gas leaks, causing particles to contaminate the transfer chamber and adhere to substrates.
Innovation Solution
Incorporating a capture part in the return path that electrically captures particles using an electrostatic force, thereby preventing particle contamination in the transfer chamber even if gas leaks occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fan is provided to actively send gas to the return path, then gas circulation is improved, but pressure in the return path increases causing differential pressure and gas leakage
Solution Approach 1:
The harmful factor (particles) is extracted from the return path gas stream by the capture part before the gas is circulated back to the transfer chamber. This removes the contamination source while maintaining the beneficial gas circulation function.
Solution Approach 2:
The capture part acts as an intermediary component between the return path and transfer chamber, intercepting particles in the gas flow and preventing them from entering the transfer chamber, thus mediating the harmful effect of gas circulation.
2Object-affected harmful factors
If particles are captured using a physical filter, then particle contamination is reduced, but flow path resistance increases
Solution Approach 1:
The mechanical filtration system is replaced with an electrostatic capture system. Instead of using physical filters that create flow resistance, the capture part uses electrostatic forces to attract and capture particles, eliminating the need for high-flow-resistance filtering components.
Solution Approach 2:
The method of particle capture is changed from physical filtration (mechanical parameter) to electrostatic attraction (electrical parameter). This parameter change allows particle removal without the flow path resistance penalty associated with physical filters.
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 capture part effectively reduces particle contamination in the transfer chamber, maintaining cleanliness and preventing particle adhesion to substrates, while also avoiding increased flow path resistance.
Implementation Method 1
a capture part provided in the return path and configured to electrically capture particles contained in the gas flowing through the return path
Data Source
AI summary
An EFEM includes a circulation path including a transfer chamber configured to form a transfer space where a substrate is transferred and a return path configured to return a gas flowing from one side to the other side of the transfer chamber, the EFEM including: a capture part provided in the return path and configured to electrically capture particles contained in the gas flowing through the return path, wherein the return path and the transfer chamber are provided such that a partition wall is interposed therebetween, and a differential pressure is generated on both sides of the partition wall such that a pressure on the side of the return path becomes higher than a pressure on the side of the transfer chamber in a state in which the gas circulates through the circulation path.