EUV Mask Contamination Removal Using Compensation Energy
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Solution Overview
Problem
Existing lithography methods fail to adequately address contamination on EUV masks, leading to critical dimension variation and reduced consistency in semiconductor manufacturing.
Innovation Solution
A lithography system equipped with a thickness measuring device using ellipsometry to measure contamination layers on EUV masks, coupled with a controller to apply compensation energy to light based on measured thickness, thereby reducing contamination and maintaining consistent critical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography methods are used without contamination removal, then manufacturing process is simpler and faster, but critical dimension variation increases and manufacturing precision deteriorates
Solution Approach 1:
The patent applies preliminary action by measuring contamination layer thickness on EUV masks before lithography processing and applying compensation energy in advance to remove contamination. This preliminary contamination removal prevents critical dimension variation during subsequent manufacturing steps, resolving the contradiction between manufacturing precision and system complexity.
Solution Approach 2:
The patent implements feedback by using thickness measuring devices to continuously monitor contamination layer thickness on masks and adjusting the compensation energy accordingly. This closed-loop feedback system maintains manufacturing precision by dynamically adapting to contamination levels without requiring overly complex manual intervention.
2Manufacturing precision
If compensation energy is applied to remove contamination, then critical dimension variation decreases, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting the energy level of incident light dynamically based on measured contamination thickness. Instead of using constant high energy, the system modulates energy parameters to match actual contamination levels, achieving critical dimension consistency while minimizing unnecessary energy consumption.
Solution Approach 2:
The patent applies partial action by applying compensation energy only when and where contamination is detected, rather than continuously applying maximum energy. This selective approach maintains manufacturing precision for contaminated areas while reducing overall energy consumption compared to continuous high-energy operation.
3Measurement precision
If thickness measuring device is added to monitor contamination, then manufacturing precision improves, but device complexity and initial cost increase
Solution Approach 1:
The patent applies universality by designing the thickness measuring device to serve multiple functions: monitoring contamination layers on masks, measuring film thickness during processing, and providing feedback for energy compensation. This multi-functionality justifies the added device complexity by eliminating the need for separate specialized measurement and control systems.
Solution Approach 2:
The patent uses the thickness measuring device as an intermediary between the contamination layer and the lithography processing system. This intermediary provides critical information about contamination status, enabling automated adjustments in the lithography process without requiring direct manual inspection or overly complex integrated control systems.
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 reduces critical dimension variation by gradually removing contamination layers, enhancing manufacturing consistency and throughput without requiring dummy substrates.
Implementation Method 1
measuring a thickness of a contamination layer formed on a mask
Implementation Method 2
applying compensation energy to light directed to the mask
Data Source
AI summary
A method is described. The method includes obtaining a relationship between a thickness of a contamination layer formed on a mask and an amount of compensation energy to remove the contamination layer, obtaining a first thickness of a first contamination layer formed on the mask from a thickness measuring device, and applying first compensation energy calculated from the relationship to a light directed to the mask.