FOUP Purging via Segmented Inlet and Outlet Pipes
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Solution Overview
Problem
Semiconductor wafers in Front Opening Unified Pods (FOUPs) are exposed to moisture and oxygen for extended periods, leading to detrimental effects, and existing purge gas methods do not efficiently reduce these contaminants to acceptable levels.
Innovation Solution
The configuration of at least one inlet pipe with exhale openings and one outlet pipe with inhale openings in the FOUP directs a gas flow between adjacent wafers, stabilizing the flow to laminar and reducing particle deposition, thereby improving purging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional inlet and outlet pipes are used in FOUP, then the structure is simple, but the gas flow becomes turbulent causing particle deposition on wafer surfaces
Solution Approach 1:
The inlet pipe is segmented into multiple exhale openings distributed along its length, and the outlet pipe is segmented into multiple inhale openings. This segmentation allows gas to be introduced and removed at multiple locations, creating a more controlled flow pattern that reduces turbulence and prevents particle deposition on wafer surfaces.
Solution Approach 2:
The patent introduces an intermediary flow control mechanism where the exhale openings and inhale openings act as intermediate points for gas exchange. This intermediary structure mediates the gas flow between the main inlet and outlet, stabilizing the flow into laminar patterns that protect wafer surfaces from particle contamination.
2Manufacturing precision
If purge gas is introduced to reduce moisture and oxygen, then contamination levels decrease, but the purging efficiency is insufficient to reach acceptable levels quickly
Solution Approach 1:
The multiple exhale and inhale openings enable continuous gas flow through the FOUP, maintaining constant purging action throughout the container. This continuous flow ensures that moisture and oxygen are consistently removed from all areas, achieving acceptable contamination levels more quickly than traditional single-point purging methods.
Solution Approach 2:
The patent transitions from single-point gas introduction and removal to a distributed multi-point system. By arranging exhale and inhale openings at different locations and heights, the purging action extends into additional spatial dimensions, improving gas exchange efficiency and accelerating the removal of moisture and oxygen throughout the FOUP volume.
3Productivity
If gas flow is increased to improve purging efficiency, then moisture and oxygen removal improves, but turbulent flow causes particle deposition on wafers
Solution Approach 1:
The patent applies local quality by positioning exhale and inhale openings at specific locations optimized for their function. The exhale openings are positioned to direct gas flow in a controlled manner, while inhale openings are positioned to efficiently remove contaminants. This localized optimization allows high purging efficiency in contaminated areas while maintaining laminar flow conditions at wafer surfaces.
Solution Approach 2:
The patent changes the flow parameters by distributing gas introduction and removal across multiple openings rather than using single large openings. This parameter change transforms the flow characteristics from high-velocity turbulent flow to lower-velocity laminar flow, achieving effective purging without causing particle deposition on sensitive wafer surfaces.
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 minimizes moisture and oxygen exposure, enhancing the purging efficiency and reducing particle contamination on wafer surfaces within the FOUP.
Implementation Method 1
the gas flow along surfaces of the wafers may be stable and approaches to a laminar flow instead of a turbulent flow
Implementation Method 2
Moisture and oxygen levels can be reduced within an enclosed FOUP by introducing a purge gas (typically N2)
Data Source
AI summary
A front opening unified pod (FOUP) includes a container, a plurality of wafer slots, at least one inlet pipe, and at least one outlet pipe. The wafer slots, the inlet pipe, and the outlet pipe are disposed in the container. The inlet pipe has a plurality of exhale openings arranged along the inlet pipe. The outlet pipe has a plurality of inhale openings arranged along the outlet pipe.