Wafer Storage Gas Isolation for Low Humidity and Oxygen Control
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Solution Overview
Problem
Semiconductor wafer storage devices face challenges in maintaining a controlled humidity and gas environment, leading to defects and yield loss due to moisture and oxygen exposure, as well as contamination from particulates and chemical gases, which are exacerbated by the scaling down of semiconductor device dimensions.
Innovation Solution
The implementation of a wafer storage device with an isolation gas device and vacuum system that maintains a relative humidity below 5% and oxygen concentration below 100 ppm, using a purge gas flow and venting system to isolate the internal environment from external contaminants and control moisture and gas levels, thereby minimizing oxide layer thickness variations and preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional storage devices are used, then device simplicity is maintained, but humidity and oxygen control capability deteriorates leading to defects
Solution Approach 1:
The storage device is divided into multiple sealed chambers (first chamber and second chamber) with independent environmental controls. Each chamber can maintain different humidity and oxygen levels, allowing targeted protection of wafers at different storage stages while keeping the overall system manageable through modular segmentation.
Solution Approach 2:
The patent implements inert atmosphere control by sealing chambers and using purge gases (nitrogen or dry air) to displace oxygen and moisture. The first chamber maintains low oxygen environment (≤1% O2) while the second chamber maintains controlled humidity (≤5% RH), creating protective inert environments that prevent oxidation and moisture-related defects without requiring complex active control systems.
2Object-affected harmful factors
If sealing measures are enhanced to prevent contamination, then protection capability is improved, but gas exchange control becomes more difficult
Solution Approach 1:
The patent extracts the gas exchange control function into a dedicated gas exchange unit that operates independently from the chamber sealing structure. This unit uses movable seals and controlled purge gas flow to enable selective gas exchange without compromising chamber sealing, allowing contamination protection while maintaining manageable gas exchange control through a specialized subsystem.
Solution Approach 2:
Purge gas (nitrogen or dry air) serves as an intermediary substance that facilitates controlled gas exchange between the external environment and sealed chambers. The purge gas displaces oxygen and moisture through controlled flow paths with movable seals, enabling indirect gas exchange that maintains sealing integrity while achieving the desired atmospheric composition changes.
3Manufacturing precision
If environmental control is intensified to reduce defects, then wafer protection is improved, but system complexity increases
Solution Approach 1:
The environmental control system is segmented into two independent chambers with distinct control parameters - the first chamber focuses on oxygen control (≤1% O2) while the second chamber focuses on humidity control (≤5% RH). This segmentation allows each subsystem to be optimized for its specific function with simpler control mechanisms, achieving high manufacturing precision without requiring a single complex unified control system.
Solution Approach 2:
The patent achieves precise wafer protection by controlling specific atmospheric parameters (oxygen concentration and relative humidity) within defined thresholds rather than attempting comprehensive environmental control. By focusing on critical parameters (O2 ≤1%, RH ≤5%) and using purge gas composition control, the system achieves high manufacturing precision with manageable complexity through parameter-based control rather than full environmental monitoring.
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 solution effectively protects semiconductor wafers from moisture and oxygen-induced defects, reduces contamination, and maintains uniform oxide thickness, enhancing production yield and wafer quality by maintaining a precise and controlled storage environment.
Implementation Method 1
A purge gas system is provided to maintain a desired gas environment within an interior volume of a storage device
Implementation Method 2
an isolation gas device and a vacuum device to maintain a desired relative humidity and gas environment
Data Source
AI summary
The present disclosure describes a storage device including a top panel, a bottom panel, a back panel, a front panel, and two side panels configured to form an enclosed volume. The storage device further includes multiple slots disposed at inner surfaces of the two side panels and configured to hold a substrate, a gas diffuser disposed at an inner surface of the back panel and configured to provide a purge gas to the enclosed volume, an isolation gas device disposed on an inner surface of the top panel and adjacent to a top portion of the front panel, and an isolation gas line configured to connect the isolation gas device to the gas diffuser. The isolation gas device is configured to inject the purge gas into a front portion of the storage device and in a direction from the top panel toward the bottom panel.