Chemical Liquid Purity Control for Defect-Safe Lithography Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The chemical liquids used in photolithography processes for semiconductor manufacturing require improved developability and defect inhibition performance, as existing solutions do not adequately address the mixing of particles and impurities that can lead to defects in semiconductor devices.
Innovation Solution
A chemical liquid comprising an organic solvent, specific metal impurities (Fe, Ni, Cr, Pb), and organic impurities, with controlled concentrations and ratios, stored in a nonmetallic or electropolished stainless steel storage tank, and filled using connection members that minimize impurity elution, along with a filling method that ensures low impurity transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high purity chemical liquid is used to prevent particle mixing and defects, then defect inhibition performance is improved, but manufacturing cost increases due to complex purification processes
Solution Approach 1:
The patent specifies precise parameter ranges for metal impurities (5-500 ppt) and organic impurities (0.1-1000 ppm) to achieve optimal defect inhibition performance. By controlling impurity levels within these specific ranges rather than requiring extreme purity, the patent balances performance with manufacturing feasibility
Solution Approach 2:
The patent uses high-purity reference chemical liquids with known impurity profiles as standards for comparison. By copying the successful impurity control strategy from these reference liquids, manufacturers can achieve defect inhibition without developing entirely new purification processes
2Reliability
If strict impurity control is implemented to improve developability and defect inhibition, then chemical liquid performance is improved, but process complexity increases
Solution Approach 1:
The patent specifies that impurity control measures should be implemented in advance during chemical liquid preparation and storage. By establishing impurity thresholds before use and selecting appropriate storage materials (nonmetallic or electropolished stainless steel) beforehand, the need for complex real-time monitoring and adjustment processes is reduced
Solution Approach 2:
The patent introduces specific intermediary substances with controlled impurity profiles that mediate between the raw chemical liquid and the final application. These intermediaries have predetermined impurity levels that facilitate subsequent processing while maintaining developability and defect inhibition performance
3Quantity of substance
If nonmetallic storage tanks are used to minimize metal impurity elution, then chemical liquid purity is improved, but storage tank cost and complexity increase
Solution Approach 1:
The patent applies different material qualities to different parts of the storage system. Nonmetallic materials are used for components that directly contact the chemical liquid (storage tanks, piping), while metallic materials with protective coatings or electropolished surfaces are used for structural support elements. This localized application of material specifications reduces overall system cost while maintaining liquid purity
Solution Approach 2:
The patent employs composite storage tank structures combining nonmetallic inner liners with metallic outer shells. The nonmetallic layer prevents metal impurity elution while the metallic provides structural strength. This composite approach achieves high purity requirements without the full cost of entirely nonmetallic storage systems
4Quantity of substance
If connection members are designed to minimize impurity transfer during filling, then impurity elution is reduced, but filling system complexity and cost increase
Solution Approach 1:
The patent specifies that connection members used during filling operations should be disposable or easily replaceable components made from nonmetallic materials. Rather than investing in complex, expensive, permanently maintainable filling systems, the approach uses inexpensive single-use connection members that eliminate metal impurity transfer without requiring complex cleaning or maintenance infrastructure
Data Source
AI summary
An object of the present invention is to provide a chemical liquid having excellent developability and excellent defect inhibition performance. Another object of the present invention is to provide a chemical liquid storage body, a chemical liquid filling method, and a chemical liquid storage method. The chemical liquid according to an embodiment of the present invention is a chemical liquid containing an organic solvent, a metal impurity, and an organic impurity, in which the metal impurity contains metal atoms, a total content of the metal atoms in the chemical liquid with respect to a total mass of the chemical liquid is equal to or smaller than 50 mass ppt, a total content of the organic impurity in the chemical liquid with respect to the total mass of the chemical liquid is 0.1 to 10,000 mass ppm, the organic impurity contains an alcohol impurity, and a mass ratio of a content of the alcohol impurity to the total content of the organic impurity is 0.0001 to 0.5.