Electrostatic Chuck Cleaning via Ultrasonic Agitation and Electric Fields
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Solution Overview
Problem
Electrostatic chucks (ESCs) in semiconductor processing equipment experience short lifetimes due to contaminant deposition, leading to dynamic alignment failures, helium gas leakage, increased dechucking time, and substrate sticking, which affects throughput and increases ownership costs.
Innovation Solution
A method involving immersing the ceramic surface of the ESC in dielectric liquid, spacing it from a conductive surface, and subjecting the liquid to ultrasonic agitation while applying voltage to remove contaminants such as organic, metallic, and electrode impurities, thereby refreshing the ceramic surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ESC is used continuously in semiconductor processing, then productivity is maintained, but contaminant deposition occurs leading to short lifetime and failures
Solution Approach 1:
The patent applies the discarding and recovering principle by implementing a cleaning process that removes contaminants from the ESC ceramic surface, effectively recovering the ESC for continued use. The cleaning method uses ultrasonic agitation with dielectric liquid to eliminate organic, metallic, and electrode impurities, allowing the ESC to be reused without replacement, thus extending its operational lifetime while maintaining productivity
Solution Approach 2:
The ESC cleaning system applies self-service principle by incorporating an automated cleaning mechanism that periodically maintains the ESC surface without requiring manual intervention or ESC replacement. The ultrasonic cleaning apparatus with dielectric liquid and voltage application creates a self-sustaining maintenance cycle that keeps the ESC in optimal condition throughout its operational life
2Productivity
If ESC operates for extended periods, then productivity increases, but dynamic alignment failure and substrate sticking occur
Solution Approach 1:
The patent applies preliminary action by performing cleaning operations before contaminants can cause dynamic alignment failure or substrate sticking. The periodic ultrasonic cleaning with dielectric liquid removes impurities that would otherwise accumulate and interfere with ESC performance, preventing alignment issues before they occur and ensuring continuous reliable operation
3Reliability
If ESC is cleaned frequently to maintain surface cleanliness, then reliability improves, but loss of time and productivity decrease
Solution Approach 1:
The patent replaces manual cleaning operations with an automated ultrasonic cleaning system that uses ultrasonic waves and dielectric liquid to remove contaminants. This mechanical-to-acoustic energy substitution enables efficient cleaning with minimal manual intervention and reduced downtime, as the ultrasonic process rapidly removes contaminants without requiring disassembly or complex manual procedures
Solution Approach 2:
The cleaning process utilizes parameter changes by applying voltage to the ESC during ultrasonic agitation in dielectric liquid. This combination of ultrasonic frequency, voltage application, and dielectric liquid properties creates optimal cleaning conditions that efficiently remove contaminants in minimal time, balancing reliability maintenance with productivity preservation
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 method effectively removes contaminants from ESC surfaces, extending the lifespan of ESCs, reducing failures, and improving the performance and reliability of plasma processing equipment by maintaining surface cleanliness.
Implementation Method 1
The dielectric liquid is subjected to ultrasonic agitation
Implementation Method 2
simultaneously applying voltage between the object and the conductive surface
Data Source
AI summary
A method of cleaning an ESC comprises immersing a ceramic surface of the ESC in dielectric fluid; spacing the ceramic surface of the ESC apart from a conductive surface such that the dielectric fluid fills a gap between the ceramic surface of the ESC and the conductive surface; and subjecting the dielectric fluid to ultrasonic agitation while simultaneously applying voltage to the ESC.