EUV Reticle Charge Neutralization via Plasma
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Solution Overview
Problem
Extreme ultraviolet (EUV) exposure apparatuses face challenges in reducing or removing particle contamination on reticles, which affects the quality of semiconductor device manufacturing.
Innovation Solution
An EUV exposure apparatus is designed with a plasma source to electrically neutralize reticles by generating plasma on the reticle surface, combined with a controller that stepwise adjusts electrostatic voltage on the reticle chuck to manage and reduce contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV light source is used to generate EUV beam for photolithography, then manufacturing precision is improved, but particle contamination on reticle increases
Solution Approach 1:
The patent applies plasma treatment to convert the harmful charged particles accumulated on the reticle into beneficial effects. The plasma neutralizes the charges and removes particle contamination, transforming the problematic charge accumulation into a controlled cleaning process that actually improves reticle quality and prevents defects
Solution Approach 2:
The patent changes the physical-chemical state of the reticle surface by applying plasma treatment. This alters the surface parameters by removing contaminants and neutralizing charges, thereby improving the reticle's cleanliness and electrical properties without changing the EUV light source itself
2Manufacturing precision
If reticle is replaced frequently due to contamination, then manufacturing precision is maintained, but productivity decreases
Solution Approach 1:
The patent applies plasma treatment during idle periods between exposures to proactively clean and neutralize the reticle before contamination becomes severe. This preliminary maintenance action prevents the need for frequent reticle replacements, maintaining productivity while ensuring reticle cleanliness
Solution Approach 2:
The patent implements continuous plasma treatment during exposure apparatus idle time, ensuring the reticle is continuously cleaned and neutralized without interrupting the exposure process. This continuous maintenance action extends reticle life and maintains productivity
3Reliability
If plasma is applied to neutralize reticle charges, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the chamber wall serve multiple functions: it acts as both the exposure chamber boundary and a plasma generation electrode. This multi-functionality allows plasma treatment to be integrated into the existing chamber structure without adding separate complex neutralization systems
Solution Approach 2:
The patent enables the reticle to be self-neutralized through plasma treatment applied to the chamber environment. The plasma automatically neutralizes charges on the reticle surface without requiring direct contact or complex targeting mechanisms, simplifying the overall system design
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 or removes particle contamination on reticles, enhancing the cleanliness and reliability of the semiconductor manufacturing process.
Implementation Method 1
a plasma source configured to provide plasma to the reticle to electrically neutralize the reticle charged by the EUV beam
Implementation Method 2
a reticle chuck on the reticle stage and configured to hold the reticle
Data Source
AI summary
An extreme ultraviolet (EUV) exposure apparatus includes a chamber, an EUV source in the chamber and configured to generate an EUV beam, an optical system above the EUV source and configured to provide the EUV beam to a substrate, a substrate stage in the chamber and configured to receive the substrate, a reticle stage in the chamber and configured to hold a reticle that is configured to project the EUV beam onto the substrate, and a plasma source configured to provide plasma to the reticle to electrically neutralize the reticle charged by the EUV beam.