Method and apparatus for enhanced cleaning and inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems are inadequate in thoroughly cleaning photomask transportation and storage pods, particularly for EUV photomasks, which are sensitive to contamination due to smaller feature sizes and lack of pellicle protection, making it difficult to ensure the pods are free of foreign particles.
Innovation Solution
A system comprising a cleaning chamber with adjustable retaining structures, a gas distributor for turbulent gas flow, a vibration generator, ultraviolet light source, and a carbon dioxide snow jet to remove particles, along with a particle collection system to determine cleanliness, ensures effective removal and detection of foreign particles from photomask pods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If photomasks are transported inside a pod, then the photomasks are protected during transportation, but foreign particles may attach to the inside of the pod and contaminate the photomasks
Solution Approach 1:
The system performs cleaning operations on the pod before the photomask is placed inside for transportation. The cleaning chamber removes foreign particles from the pod interior using gas flow, vibration, and ultrasonic treatment before the pod is sealed and transported, preventing contamination from occurring in the first place
Solution Approach 2:
The patent introduces a particle collection surface as an intermediary element that captures foreign particles during the cleaning process. This collection surface acts as a mediator between the cleaning mechanisms and the pod, allowing particles to be trapped and removed rather than directly contacting the photomask
2Manufacturing precision
If EUV photomasks are used with smaller feature sizes, then lithography precision is improved, but the photomasks become more sensitive to contamination
Solution Approach 1:
The cleaning system uses multiple parameters including gas flow rate, vibration frequency, and ultrasonic power that can be adjusted based on the specific contamination risks. For EUV photomasks with smaller features, the system can intensify cleaning parameters to achieve higher cleanliness levels without damaging the sensitive photomask structures
Solution Approach 2:
The system applies more thorough cleaning than traditionally necessary by using multiple cleaning mechanisms simultaneously (gas flow, vibration, ultrasonic). This excessive cleaning action ensures that even the smallest particles that could contaminate high-precision EUV photomasks are completely removed
3Object-affected harmful factors
If a pellicle is used to protect the photomask, then contamination is reduced, but the system complexity increases
Solution Approach 1:
The patent extracts the protection function from the photomask itself (by removing the pellicle) and places it in the transportation system through rigorous cleaning of the pod. This eliminates the need for the pellicle structure while maintaining protection, as the pod is cleaned to such high standards that no contamination reaches the photomask during transport
4Device complexity
If traditional cleaning methods are used on the pod, then the cleaning process is simple, but it is difficult to determine if the pod is substantially free of foreign particles
Solution Approach 1:
The system incorporates a particle detection mechanism that provides feedback on the cleanliness of the pod after cleaning. The particle collection surface is inspected to determine whether any foreign particles remain, allowing the system to verify cleaning effectiveness and determine when the pod is sufficiently clean for photomask transportation
Solution Approach 2:
The patent replaces subjective visual inspection with an automated particle detection system that uses optical or other sensing mechanisms to objectively measure the presence of foreign particles on the particle collection surface, providing precise measurement of cleaning effectiveness
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 system effectively removes particles as small as 10-35 nm, ensuring the cleanliness of photomask pods, thereby preventing contamination during transportation and enhancing the reliability of lithography processes.
Implementation Method 1
distributing a turbulent flow of gas into the cleaning chamber to facilitate the removal of any foreign particles attached to a surface of the article
Implementation Method 2
The cleaning and inspection system includes a vibration generator configured to impart movement to the article so that any foreign particles detached from the article are removed from the article
Implementation Method 3
The cleaning and inspection system includes a distribution of an ultraviolet light into the cleaning chamber that neutralizes any electrically charged foreign particles attached to a surface of the article
Implementation Method 4
a jet of carbon dioxide snow configured to remove any foreign particles detached from the article
Data Source
AI summary
A cleaning and inspection system includes a cleaning chamber and retaining structure disposed within the cleaning chamber and configured to secure an article to be cleaned within the cleaning chamber. The cleaning and inspection system also includes a gas distributor disposed within the cleaning chamber and configured to distribute a turbulent flow of gas into the cleaning chamber that facilitates removal of foreign particles from a surface of the article. Further, the system includes a particle collection surface positioned to collect foreign particles removed from the surface of the article.