Pellicle Aging Estimation via Acoustic Resonance
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Solution Overview
Problem
Existing methods for determining pellicle aging in lithography processes are inadequate, as they fail to accurately assess the aging condition and often damage the pellicle or the mask during contaminant particle removal, leading to potential mask damage and inefficient pellicle replacement.
Innovation Solution
The use of acoustic waves to estimate the age condition of pellicles by forcing them into specific modes of oscillation and measuring the shift in resonance frequency, allowing for non-invasive monitoring and removal of contaminant particles without direct mechanical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods are used to determine pellicle aging, then the aging assessment is performed, but the accuracy of aging assessment is insufficient
Solution Approach 1:
The patent applies mechanical vibration by generating acoustic waves that cause the pellicle to vibrate at its resonance frequency. The resonance frequency is directly correlated with the pellicle's mechanical properties and aging state, enabling accurate non-contact assessment of pellicle condition without physical contact or damage
Solution Approach 2:
The patent replaces traditional mechanical contact-based aging assessment methods with acoustic wave-based resonance measurement. This substitution eliminates the need for physical contact with the pellicle, thereby preventing mechanical damage while maintaining or improving measurement accuracy
2Object-generated harmful factors
If existing methods are used to remove contaminant particles from pellicle, then particle removal is achieved, but the pellicle is damaged
Solution Approach 1:
The patent uses mechanical vibration at the pellicle's resonance frequency to remove contaminant particles. The resonant vibration creates sufficient force to dislodge particles from the pellicle surface while the non-contact nature of the acoustic waves prevents damage to the pellicle itself
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to remove contaminants. The acoustic waves act as a mediator that transfers energy to dislodge particles without requiring direct mechanical contact between removal tools and the pellicle, thereby preventing pellicle damage
3Object-generated harmful factors
If existing methods are used to remove contaminant particles from pellicle, then particle removal is achieved, but the mask is damaged
Solution Approach 1:
The patent uses acoustic waves as an intermediary to remove particles from the pellicle without direct contact with the mask. The acoustic waves penetrate or act through the pellicle to dislodge particles, preventing the need for tools that might accidentally contact and damage the underlying mask
Solution Approach 2:
The patent replaces mechanical particle removal systems that could contact the mask with acoustic wave-based removal. This substitution eliminates the risk of mechanical tools damaging the mask while effectively removing contaminants from the pellicle
4Object-generated harmful factors
If traditional particle removal methods are used, then contaminant particles are removed, but the process is invasive and potentially damaging
Solution Approach 1:
The patent replaces invasive mechanical particle removal methods with acoustic wave-based removal. The acoustic waves provide a non-contact, non-invasive mechanism to dislodge and remove particles from the pellicle surface without the need for physical tools that could cause damage
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
This method provides a fast, accurate, and minimally invasive way to determine pellicle aging, preventing damage to the lithography mask and optimizing pellicle usage, while effectively removing contaminant particles without damaging the pellicle.
Implementation Method 1
forcing them into specific modes of oscillation and measuring the shift in resonance frequency
Implementation Method 2
removal of contaminant particles from the pellicle using acoustic waves
Data Source
AI summary
A pellicle is disposed over a lithography mask. An acoustic wave generator is placed over the pellicle. The acoustic wave generator is configured to generate acoustic waves to cause the pellicle to vibrate at a target resonance frequency. A resonance detection tool is configured to detect an actual resonance frequency of the pellicle in response to the acoustic waves. One or more electronic processors are configured to estimate an age condition of the pellicle as a function of a shift of the actual resonance frequency from the target resonance frequency.