Reticle Enclosure ESD Coating for Particle-Free EUV Handling
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Solution Overview
Problem
Residual electrostatic charges on reticles in extreme ultraviolet (EUV) lithography systems attract particulate matter, leading to contamination and fabrication errors during semiconductor processing.
Innovation Solution
An EUV reticle pod with a coating on its surfaces to reduce electrostatic charges, limiting the attraction of particles to the reticle and maintaining a cleaner environment within the lithography system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a reticle is stored in a mask case (pod) during transport and storage, then the reticle is protected from contamination such as dust or particles, but residual electrostatic charges on the reticle attract particulate matter, leading to contamination and fabrication errors
Solution Approach 1:
The patent introduces an electrostatic discharge (ESD) coating as an intermediary layer between the reticle and the pod interior surfaces. This coating material serves as a mediator that safely dissipates electrostatic charges from the reticle, preventing the attraction of particulate matter while maintaining the protective enclosure environment
Solution Approach 2:
The patent modifies the electrical properties of the pod interior surfaces by applying ESD coatings to the base and cover surfaces. This changes the static electrical parameter of the surfaces from charge-attracting to charge-dissipating, fundamentally altering how the environment interacts with the reticle's electrostatic field
2Productivity
If the reticle is handled and transferred between storage and lithography apparatus, then the lithography process can proceed, but residual electrostatic charges are generated that attract particles to the reticle
Solution Approach 1:
The patent applies electrostatic discharge coatings to the pod surfaces before the reticle is placed inside. This preliminary action ensures that the environment is pre-conditioned to be electrostatically safe, so that when the reticle is handled and transferred, charges do not accumulate to problematic levels
Solution Approach 2:
The ESD coating materials possess inherent charge-dissipating properties that automatically neutralize electrostatic charges on the reticle without requiring external intervention. The coating self-services the electrostatic management function throughout the storage and handling process
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 solution effectively reduces residual electrostatic charges on reticles, minimizing particle deposition and contamination, thereby enhancing the accuracy and reliability of EUV lithography processes.
Implementation Method 1
a layer of electrostatic discharge material disposed on the first surface, wherein the electrostatic discharge material reduces electrostatic charges on the reticle when the reticle is placed in or removed from the reticle enclosure
Data Source
AI summary
A reticle enclosure includes a base including a first surface, a cover including a second surface and disposed on the base, wherein the base and the cover form an internal space therebetween that includes a reticle, and a layer of electrostatic discharge material disposed on the first surface, wherein the electrostatic discharge material reduces electrostatic charges on the reticle.