Substrate Container Purging With Density-Matched Gas Flow
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Solution Overview
Problem
Commercial substrate container purge processes using either nitrogen or clean dry air result in non-uniform purging due to density differences, leading to inefficient and time-consuming moisture removal from the container atmosphere, especially affecting upper and lower container locations.
Innovation Solution
A method and system that control the density of the purge gas by mixing clean dry air and nitrogen, or adjusting the temperature of a single gas to match the density of the humid air within the container, ensuring uniform flow and efficient displacement of the container atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nitrogen gas is used as purge gas, then oxygen level in container is lowered, but purging uniformity deteriorates due to density difference
Solution Approach 1:
The patent controls the temperature of nitrogen gas to adjust its density, matching it to the density of humid air in the container. This parameter change (temperature control) allows nitrogen to effectively displace humid air uniformly throughout the container while maintaining low oxygen levels, resolving the contradiction between oxygen reduction and purging uniformity
Solution Approach 2:
The system uses density sensors to monitor the density of purge gas and container atmosphere, with control systems that adjust nitrogen gas temperature based on feedback signals. This closed-loop feedback mechanism ensures continuous optimization of purging uniformity while maintaining low oxygen conditions
2Ease of manufacture
If clean dry air is used as purge gas, then purging cost is reduced, but purging uniformity deteriorates due to density difference
Solution Approach 1:
The patent applies temperature control to adjust the density of clean dry air to match the density of humid air in the container. This parameter modification enables uniform purging throughout the container using cost-effective clean dry air, eliminating the density-driven non-uniformity while maintaining low cost
3Device complexity
If purge gas density is not controlled, then device complexity is reduced, but purging time increases due to non-uniform flow
Solution Approach 1:
The patent implements temperature control of purge gas to match densities, creating uniform flow patterns that significantly reduce purging time. The relatively simple temperature adjustment mechanism achieves this time reduction without substantially increasing device complexity
Solution Approach 2:
The system employs periodic purging cycles with controlled temperature stages, where nitrogen gas is heated to specific temperatures during different phases of the purging process. This periodic temperature control achieves uniform purging and reduced time without requiring continuously complex equipment
4Stability of the object's composition
If purge gas temperature is increased to match density, then purging uniformity is improved, but energy consumption increases
Solution Approach 1:
The patent makes temperature a controllable parameter of purge gas, adjusting it to match the density of humid air. This single parameter change achieves uniform purging while the energy required for heating remains relatively modest compared to the benefits of reduced purging time and improved uniformity
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 controlled density purge gas achieves faster and more uniform purging across the container, reducing the time required for the purge step and enhancing the overall efficiency of the manufacturing process.
Implementation Method 1
controlling the density of the purge gas to match a density of the humid air within the container interior
Implementation Method 2
dispensing purge gas through the one or more inlets to the interior... ensuring uniform flow and efficient displacement of the container atmosphere
Data Source
AI summary
Described are substrate containers that are useful for holding or transporting substrates such as semiconductor wafers and microelectronic devices, in a clean environment, as well as methods of using the substrate containers.