Electrostatic Chuck Particle Removal Using Rotating Vacuum Cleaning
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Solution Overview
Problem
Contamination on electrostatic chucks in EUV semiconductor lithography processes leads to photomask deformation and performance deterioration due to particle contamination, which existing methods fail to adequately address.
Innovation Solution
An electrostatic chuck cleaning tool and method utilizing a platform with a spindle, motor, casing, and vacuum source, along with optical inspection instruments, to detect and remove particles using rotation, adhesive materials, ultrasound, and photo-catalyst materials, while a vacuum source collects and filters particles to prevent re-contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing cleaning methods are used on electrostatic chucks, then cleaning operation is simple, but particle contamination is not adequately removed leading to photomask deformation
Solution Approach 1:
The cleaning tool is divided into multiple functional modules: a platform for holding the electrostatic chuck, a spindle for rotation, a vacuum source for particle collection, and an optical inspection instrument for detection. This segmentation allows each component to perform its specific function efficiently while maintaining overall system effectiveness in removing particle contamination.
Solution Approach 2:
The patent introduces an optical inspection instrument as an intermediary to detect particles on the electrostatic chuck before cleaning. This intermediary component enables precise identification of contamination locations, allowing the cleaning process to target specific areas and improve overall cleaning effectiveness without requiring excessive mechanical complexity.
2Reliability
If multiple cleaning mechanisms are implemented, then particle removal effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple cleaning mechanisms into a single integrated platform: rotation of the platform provides mechanical agitation, adhesive materials on the platform capture particles, and ultrasound generates vibrations to dislodge contaminants. This combination of mechanisms works synergistically to improve cleaning reliability while containing device complexity within a unified structure.
Solution Approach 2:
The platform serves multiple functions simultaneously: it holds the electrostatic chuck, rotates to provide mechanical cleaning action, supports adhesive materials for particle capture, and facilitates ultrasound transmission. This multi-functionality reduces the need for separate dedicated components for each cleaning mechanism, thereby managing device complexity while maintaining high cleaning effectiveness.
3Measurement precision
If optical inspection instrument is used to detect particles, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
The optical inspection instrument performs preliminary detection of particles on the electrostatic chuck before the cleaning process begins. This preliminary action identifies contamination locations in advance, allowing the subsequent cleaning mechanisms to target specific areas efficiently. By detecting particles beforehand, the system achieves high measurement precision without requiring continuous complex monitoring during the entire cleaning process.
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 detects and removes particles from electrostatic chucks, minimizing contamination and improving wafer pattern transfer accuracy, reducing machine downtime and photomask damage costs.
Implementation Method 1
an electrostatic chuck (also known as an R-chuck, an E-chuck, or an ESC) is configured to hold a reflection-type mask through electrostatic forces
Implementation Method 2
a vacuum source is provided to draw the particle into the vacuum source using suction force
Implementation Method 3
transmitting a radiation toward the electrostatic chuck, receiving a reflection of the radiation, and analyzing the reflection of the radiation
Data Source
AI summary
A method includes detecting a location of a particle on a bottom surface of an electrostatic chuck; moving a platform to a position under the bottom surface of the electrostatic chuck and right under the particle; and rotating the platform about a center of the platform to remove the particle from the bottom surface of the electrostatic chuck.