External Electron Neutralization for EUV Reticle Contamination
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Solution Overview
Problem
The challenge of preventing contamination of extreme ultra-violet (EUV) reticles in EUV exposure processes, particularly due to the adherence of fine particles caused by electrostatic attraction, which can lead to defects in semiconductor wafers and reduced productivity.
Innovation Solution
A contamination prevention device for EUV reticles that includes electron sources positioned outside the EUV reticle and slit-plate space, emitting electrons to neutralize the reticle surface and counteract electrostatic charges, using sensors to detect plasma and surface charges for real-time neutralization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electron sources are positioned inside the space between the EUV reticle and slit-plate, then neutralization effect is enhanced, but device complexity and risk of contamination increase
Solution Approach 1:
The patent positions electron sources outside the critical space between the EUV reticle and slit-plate, using this external positioning as an intermediary approach to deliver electrons to the reticle surface without placing components directly in the exposure path. This mediator positioning reduces device complexity and contamination risk while maintaining neutralization effectiveness through optimized electron emission geometry.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement (inside the reticle-slit-plate space) to a three-dimensional external positioning strategy. By placing electron sources outside this space and angling their emission, the system achieves neutralization from a different spatial dimension, reducing interference with the exposure process while maintaining effectiveness.
2Measurement precision
If multiple sensors are added to detect plasma and surface charges, then neutralization control precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback control system where sensors detect plasma presence and surface charge conditions, and this information feeds back to control the electron source operation. This feedback mechanism enables precise neutralization control by adjusting electron emission based on real-time detection of reticle charge state and plasma conditions.
Solution Approach 2:
The system uses self-service detection where sensors automatically monitor plasma and surface charge conditions without external intervention, and the control system autonomously adjusts electron emission parameters. This self-monitoring and self-adjusting capability improves measurement precision while minimizing the need for additional complex external 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
Effectively prevents contamination by neutralizing the EUV reticle, reducing particle adherence and facilitating easy removal, thereby enhancing process reliability and productivity.
Implementation Method 1
at least one electron source including a first electron source on a first side of the EUV reticle outside a space between the EUV reticle and a slit-plate, wherein, during an EUV exposure process, the at least one electron source is configured to emit the electrons into the space to neutralize the EUV reticle
Implementation Method 2
emit the electrons into the space to neutralize the EUV reticle
Implementation Method 3
a first sensor in the space adjacent to a slit position of the slit-plate, the first sensor being configured to detect plasma in an EUV exposure process
Implementation Method 4
a second sensor in the space adjacent to the slit position of the slit-plate, the second sensor being configured to measure a surface charge of the EUV reticle
Data Source
AI summary
Provided is a contamination prevention device configured to prevent contamination of extreme ultra-violet (EUV) reticle, including at least one electron source including a first electron source on a first side of the EUV reticle outside a space between the EUV reticle and a slit-plate, wherein, during an EUV exposure process, the at least one electron source is further configured to emit the electrons into the space to neutralize the EUV reticle.