EFEM Return-Path Filtration for Substrate Particle Control
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Solution Overview
Problem
Existing EFEMs suffer from particle contamination in the substrate transfer space due to pressure differences between the return path and substrate transfer space, allowing particles to leak and contaminate the substrate.
Innovation Solution
An EFEM design with a partition wall separating the substrate transfer space and return path, incorporating a capture part in the return path to trap particles, and connecting pipes guiding gas from devices like the substrate transfer robot and aligner to the return path upstream of the capture part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a partition wall is used to separate the substrate transfer space and return path, then the substrate transfer space can be isolated from particle contamination, but pressure difference causes gas leakage from return path to substrate transfer space carrying particles
Solution Approach 1:
A filter is introduced as an intermediary component in the return path to capture particles from the gas flow before it can leak into the substrate transfer space. The filter acts as a mediator that allows gas passage while blocking particles, resolving the contradiction between maintaining pressure difference and preventing particle contamination.
Solution Approach 2:
The filter is strategically positioned at a specific location in the return path where gas flow and particle concentration are highest. This local intervention creates a zone of high particle capture efficiency without affecting the overall pressure difference control system, allowing targeted particle removal while maintaining system reliability.
2Productivity
If devices like substrate transfer robot and aligner operate in substrate transfer space, then substrate processing can be performed, but particles are generated and swirl upward during device operation
Solution Approach 1:
The harmful particles generated by devices are extracted from the substrate transfer space through the return path. The filter in the return path captures these particles, effectively removing them from the system before they can contaminate substrates, while allowing the devices to continue operating productively.
Solution Approach 2:
The return path, which originally served only to circulate gas, is transformed into a beneficial particle capture system. The gas flow that carries particles away from devices is now utilized to transport particles to the filter, converting the harmful particle-laden flow into a useful particle removal mechanism.
3Use of energy by stationary object
If return path pressure is higher than substrate transfer space pressure, then gas circulation is maintained, but particles in return path leak through partition wall gaps into substrate transfer space
Solution Approach 1:
The filter serves as an intermediary barrier in the return path that allows gas circulation to continue while blocking particle leakage. It mediates between the need for pressure-driven gas flow and the need to prevent particle contamination, allowing both functions to coexist.
Solution Approach 2:
The filter changes the physical parameters of the gas flow by removing particles while maintaining gas pressure and flow characteristics. This parameter modification allows the system to maintain beneficial gas circulation while eliminating harmful particle transport.
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 reduces particle contamination in the substrate transfer space by capturing particles generated within devices, maintaining cleanliness and preventing adhesion to substrates.
Implementation Method 1
a capture part provided in the return path having a higher pressure than the substrate transfer space in a state in which the gas circulates through the circulation path, and configured to capture particles contained in the gas flowing through the return path
Data Source
AI summary
An EFEM is provided with a circulation path including a substrate transfer space formed inside a housing and a return path configured to return gas flowing from one side to the other side of the substrate transfer space, the EFEM including: a partition wall configured to separate the substrate transfer space and the return path; a capture part provided in the return path having a higher pressure than the substrate transfer space in a state in which the gas circulates through the circulation path, and configured to capture particles contained in the gas flowing through the return path; and a connecting pipe configured to guide the gas flowing inside a predetermined device arranged in the substrate transfer space to the return path, wherein the connecting pipe is connected to the return path on an upstream side of the capture part in a gas flow direction.