EUV Mask Pod Cleaning via Gas, Vibration, and Snow Jets
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Solution Overview
Problem
The semiconductor industry faces challenges in maintaining the cleanliness of EUV photomasks and their transportation pods due to sensitivity to contamination and the inability to use pellicles for protection, leading to potential particle transfer during handling and transportation.
Innovation Solution
A system comprising a mask inspection tool and a mask pod inspection tool, which includes a cleaning chamber, a pass-through chamber, and a particle collection chamber, is used to remove foreign particles from photomask transportation pods. The system employs gas distribution, vibration, ultraviolet light, and carbon dioxide snow jets to effectively clean the pods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photomasks are transported inside a pod without pellicle protection, then the photomask can be used for EUV lithography, but foreign particles may transfer to the photomask during transportation
Solution Approach 1:
The system performs preliminary cleaning of the photomask pod using gas distribution, vibration, ultraviolet light, and carbon dioxide snow jets before the photomask is loaded. This advance cleaning action removes potential contaminants from the pod interior, preventing particle transfer to the photomask during subsequent transportation and inspection processes.
Solution Approach 2:
The system uses purified gas flows to create a clean environment within the cleaning chamber during the cleaning process. This controlled atmosphere minimizes the presence of airborne particles and contaminants that could otherwise settle on the photomask or pod surfaces.
2Object-affected harmful factors
If a photomask pod is thoroughly cleaned before use, then particle contamination is reduced, but the processing time and system complexity increase
Solution Approach 1:
The cleaning process is designed to operate continuously and efficiently using simultaneous multi-mode cleaning actions (gas flow, vibration, UV irradiation, and snow jetting). This continuous multi-pronged approach maximizes cleaning effectiveness within a minimized time frame, avoiding sequential processing delays.
Solution Approach 2:
Vibration is applied to the pod during cleaning to mechanically dislodge and remove particles from surfaces. This mechanical action enhances the effectiveness of other cleaning methods (gas flow, UV, snow jets) by physically disrupting particle adhesion, thereby reducing the time required for thorough cleaning.
3Object-affected harmful factors
If multiple cleaning methods are used to clean the photomask pod, then cleaning effectiveness is improved, but the device complexity increases
Solution Approach 1:
The system merges multiple cleaning methods (gas distribution, vibration, ultraviolet light, and carbon dioxide snow jets) into a single integrated cleaning chamber and control system. This consolidation allows simultaneous operation of all cleaning modes through unified control, reducing the complexity that would arise from separate standalone cleaning systems.
Solution Approach 2:
The cleaning chamber is designed as a multi-functional unit that can perform various cleaning actions (chemical, mechanical, thermal, and photonic cleaning) within a single device. This universal design eliminates the need for multiple separate cleaning devices, thereby managing system complexity while maintaining comprehensive cleaning capability.
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 ensures that EUV photomasks and their pods are thoroughly cleaned, reducing the risk of particle contamination and maintaining the integrity of the lithography process, thereby enhancing the production efficiency and quality of semiconductor integrated circuits.
Implementation Method 1
The system employs gas distribution
Implementation Method 2
The system employs gas distribution, vibration
Implementation Method 3
The system employs gas distribution, vibration, ultraviolet light
Implementation Method 4
The system employs gas distribution, vibration, ultraviolet light, and carbon dioxide snow jets
Data Source
AI summary
A method and a system for inspecting an extreme ultra violet mask and a mask pod for such masks is provided. An EUV mask inspection tool inspects a mask retrieved from a mask pod placed on the load port positioned exterior of the mask inspection tool. The inspection process is performed during a selected period of time. After the inspection process is initiated, a robotic handling mechanism such as a robotic arm or an AMHS picks up the mask pod and inspects the mask pod for foreign particles. A mask pod inspection tool determines whether the mask pod needs cleaning or replacing based on a selected swap criteria. The mask pod is retrieved from the mask pod inspection tool and placed on the load port before the selected period of time lapses. This method and system promotes a reduction in the overall time required for inspecting the mask and the mask pod.