Pellicle Cleaning With an Electrified Tip for Particle Removal
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Solution Overview
Problem
The contamination of reflective masks in EUV exposure devices due to particles during the exposure process is a challenge, necessitating the use of a pellicle to protect the mask, but existing methods are inadequate for effectively removing particles from the pellicle.
Innovation Solution
A pellicle cleaning method involving a stage rotation, tip electrification, and particle removal using a sharp tapered tip to push particles horizontally, along with a control unit to manage forces for efficient particle detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a pellicle is used to protect the reflective mask, then mask contamination is prevented, but particle accumulation on the pellicle occurs
Solution Approach 1:
The pellicle serves as an intermediary protective layer between the reflective mask and the contamination environment. It absorbs particles that would otherwise contaminate the mask, allowing the mask to remain clean while the pellicle accumulates particles that can be separately cleaned or replaced.
2Productivity
If existing cleaning methods are used on the pellicle, then some particles are removed, but the pellicle is damaged
Solution Approach 1:
The patent replaces traditional mechanical cleaning methods (such as contact-based wiping or scratching) with electrostatic force. By electrifying the tip, particles are removed through electrostatic attraction and lifting forces, eliminating the need for mechanical contact that would damage the delicate pellicle structure.
Solution Approach 2:
The patent changes the physical state or properties of the cleaning tool by electrifying the tip. This parameter change (adding electrical charge) enables the tip to interact with particles through electrostatic forces rather than mechanical contact, allowing effective particle removal without compromising pellicle integrity.
3Productivity
If a sharp tapered tip is used to push particles horizontally, then particle removal efficiency is improved, but tip electrification control complexity increases
Solution Approach 1:
The patent employs dynamic control of the electrification process, where the electrical charge on the tip is adjusted in real-time based on the cleaning progress and particle characteristics. This dynamic parameter adjustment optimizes particle removal efficiency while managing the complexity of electrification control through adaptive feedback mechanisms.
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 method efficiently removes particles from the pellicle without damaging it, ensuring the cleanliness of the reflective mask and preventing contamination of the pellicle cleaning apparatus.
Implementation Method 1
electrifying a tip; and removing particles from the pellicle, wherein removing of the particles from the pellicle includes pushing of the particles on the pellicle with the electrified tip
Data Source
AI summary
A pellicle cleaning method includes loading a pellicle on a first surface of a stage, rotating the stage about an axis parallel to the first surface, electrifying a tip; and removing particles from the pellicle, wherein removing of the particles from the pellicle includes pushing of the particles on the pellicle with the electrified tip.