Storage Case Cleaning via Gas Flow Desorption
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Solution Overview
Problem
Conventional wet cleaning methods for storage cases used in semiconductor and photomask storage are inefficient for complex shapes and metal components, leading to residual contaminants that cause device failures and increase production costs.
Innovation Solution
A dry cleaning method using air or inert gas flow at controlled temperatures to desorb and remove adsorbed sulfuric acid ions and other contaminants from storage case surfaces, preventing their transfer to substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet cleaning method is used for storage case, then cleaning ability is improved, but equipment complexity and environmental countermeasure requirements increase
Solution Approach 1:
The patent replaces the wet cleaning mechanical system (washing machines, water supply, drainage) with a simple gas flow system. Cleaned air or inert gas flows through the storage case to remove contaminants, eliminating the need for complex wet cleaning equipment while achieving effective cleaning of ion-adhered contaminants.
Solution Approach 2:
The invention uses pneumatic principles by utilizing gas flow (cleaned air or inert gas) to transport and remove contaminants from the storage case. The gas flow carries away adhered ions and foreign substances without requiring liquid solvents or complex hydraulic systems.
2Manufacturing precision
If wet cleaning method is used for storage case, then cleaning effect is improved, but environmental countermeasure requirements and production cost increase
Solution Approach 1:
The patent uses inexpensive cleaned air or inert gas that can be freely discharged after use, replacing expensive solvents and the environmental infrastructure required for their disposal. The gas serves as a disposable cleaning medium that eliminates waste treatment costs.
Solution Approach 2:
The invention extracts and removes the problematic elements (water, solvents, and their associated environmental countermeasures) from the cleaning process, retaining only the essential cleaning function through gas flow. This extraction eliminates the need for expensive environmental compliance infrastructure.
3Manufacturing precision
If wet cleaning method is used for storage case, then cleaning capability is improved, but adaptability to complicated shapes and metal parts decreases
Solution Approach 1:
The patent uses gas flow that can easily penetrate and reach all surfaces of the storage case, including complicated shapes and metal parts. The pneumatic cleaning method adapts to any geometry without requiring modification of the storage case or specialized cleaning equipment for different shapes.
Solution Approach 2:
The gas flow cleaning system serves as a universal cleaning method that works effectively on all storage case materials (including metal parts) and shapes without requiring different cleaning approaches. It replaces multiple specialized wet cleaning procedures with a single adaptable method.
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
Facilitates regular and effective cleaning of storage cases without large-scale equipment, reducing production costs and improving substrate quality by preventing ion-generated foreign substances.
Implementation Method 1
a step of placing the storage case still in the air flow of cleaned air or an inert gas in a temperature range from room temperature to 80° C. for desorbing and removing the above-mentioned foreign substances adhered on the storage case
Data Source
AI summary
The present invention provides a method of cleaning a storage case to be used for storing or transporting mask substrates such as photomasks and photomask blanks, semiconductor substrates such as semiconductor wafers, pellicles, or the like. The present invention: facilitates a regular cleaning operation, can be used also for a storage case of a complicated shape, does not require a large scale equipment or an expensive equipment to facilitate an environmental countermeasure, and provides high cleaning effect. The method of cleaning a storage case polluted by adhesion of a foreign substance of an organic material, an ionic foreign substances or an ionic crystal foreign substance physically absorbed, comprises a step of placing the storage case still in air flow of cleaned air or an inert gas in a temperature range from room temperature to 80° C. for desorbing and removing the foreign substance adhered to the storage case.