Vacuum Reticle Stage Cleaning via UV-Curing Particle Capture
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the rapid attenuation of extreme ultraviolet (EUV) light in the atmosphere, which requires the entire EUV exposure unit, including the reticle stage, to be in a vacuum chamber, making it difficult to clean the reticle stage without breaking the vacuum, leading to reduced throughput due to prolonged vacuum re-establishment times and increased particle-related defects.
Innovation Solution
A cleaning reticle with a substrate and an ultraviolet-curing or extreme ultraviolet-curing layer is used, allowing for the removal of particles from the reticle stage within a continuous vacuum atmosphere by pressing and peeling the curing layer, which is then recycled and reformed, enabling continuous operation without exposing the vacuum chamber to the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reticle stage is cleaned by opening the vacuum chamber to the atmosphere, then particles on the reticle stage can be removed, but the operational time is lost and throughput decreases
Solution Approach 1:
The patent applies the inert atmosphere principle by performing the cleaning operation within the vacuum environment itself, using a cleaning reticle that operates in the vacuum chamber without requiring atmospheric exposure. This resolves the contradiction by enabling effective particle removal while maintaining the vacuum seal, thus preserving operational time and throughput.
2Reliability
If the vacuum chamber is opened to clean the reticle stage, then particles are removed, but about half a day to a whole day is needed to re-establish vacuum
Solution Approach 1:
The cleaning reticle enables particle removal operations to be conducted within the vacuum chamber's inert vacuum atmosphere, eliminating the need to break the vacuum seal. This resolves the time loss contradiction by maintaining continuous vacuum conditions throughout the cleaning process, preventing half-day to whole-day delays associated with vacuum re-establishment.
3Manufacturing precision
If particles remain on the reticle stage, then the reticle deflects and flatness decreases, but cleaning requires breaking vacuum
Solution Approach 1:
The cleaning reticle operates within the vacuum chamber's inert atmosphere to remove particles that would otherwise cause reticle deflection and flatness degradation. This resolves the contradiction by enabling precision-maintaining cleaning operations without requiring complex vacuum chamber opening and closing procedures, thus preserving both reticle flatness and operational simplicity.
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 allows for efficient cleaning of the reticle stage without breaking the vacuum, increasing the operational rate of the EUV exposure apparatus and reducing particle-related defects, while also extending the life of the cleaning reticle components by allowing the quartz substrate to be reused.
Implementation Method 1
an ultraviolet-curing layer is formed on the substrate, and the ultraviolet-curing layer cures when irradiated with the ultraviolet rays
Data Source
AI summary
In one embodiment, a method for cleaning a reticle stage of an extreme ultraviolet exposure apparatus is disclosed. The method can include pressing a particle catching layer of a cleaning reticle onto the reticle stage, and the cleaning reticle includes the particle catching layer formed on a substrate. The method can include peeling the cleaning reticle from the reticle stage. The method can include removing the particle catching layer from the substrate. I addition, the method can include forming a new particle catching layer on the substrate having the particle catching layer removed.