Electrostatic Chuck Protective Cover for Plasma Cleaning
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Solution Overview
Problem
Electrostatic chucks used in processing chambers suffer from surface feature erosion during cleaning, leading to increased leakage rates of heat conductive fluids due to the degradation of sealing bands and mesas, which reduces their lifespan and efficiency.
Innovation Solution
A protective cover with a plasma-resistant ceramic portion and a conductive portion is used to shield the electrostatic chuck from corrosive plasmas during cleaning, extending the chuck's lifespan by preventing erosion and maintaining fluid containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrostatic chuck is cleaned using plasma or corrosive chemistries, then the processing chamber is cleaned effectively, but the surface features (sealing band and mesas) of the electrostatic chuck are eroded, increasing leakage rates
Solution Approach 1:
A protective cover is introduced as an intermediary component between the corrosive plasma/chemistries and the electrostatic chuck. The cover shields the chuck's surface features during cleaning, allowing aggressive cleaning methods to be used without eroding the sealing band and mesas, thus maintaining fluid containment capability while improving cleaning effectiveness
Solution Approach 2:
The protective cover is designed as a sacrificial, replaceable component that protects the expensive electrostatic chuck. The cover can be easily replaced when worn, allowing continuous operation without damaging the main chuck assembly. This disposable approach enables frequent cleaning cycles while preserving the chuck's integrity
2Manufacturing precision
If the electrostatic chuck is cleaned frequently to maintain processing quality, then substrate processing quality is maintained, but the lifespan of the electrostatic chuck is reduced due to cumulative erosion
Solution Approach 1:
The protective cover serves as a mediator that allows frequent cleaning operations to be performed without cumulative erosion of the chuck. By absorbing the erosive effects over time, the cover enables maintenance of substrate processing quality through regular cleaning while preserving the chuck's surface features and extending its operational lifespan
Solution Approach 2:
The protective cover is installed in advance before cleaning operations begin, providing pre-protection against erosion. This preliminary protective measure allows the chuck to undergo multiple cleaning cycles without suffering cumulative damage, thereby extending lifespan while maintaining the ability to perform frequent quality-critical cleanings
3Reliability
If the sealing band and mesas are maintained smooth and intact, then fluid leakage is minimized, but cleaning processes that remove contaminants also erode these surface features
Solution Approach 1:
The protective cover acts as a shield that blocks harmful plasma and corrosive chemistries from directly contacting the sealing band and mesas during cleaning. This intermediary protection allows thorough cleaning of contaminants while preventing erosion of the surface features, maintaining both fluid containment capability and surface integrity
Solution Approach 2:
The protective cover is designed as a sacrificial component that takes the place of the sealing band and mesas during cleaning exposure. While the cover gradually erodes, it protects the critical surface features from damage, allowing them to maintain their smooth, intact condition for fluid containment while the cover is replaced periodically
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 protective cover significantly prolongs the lifespan of electrostatic chucks from 100-200 RFHrs to up to 5000 RFHrs, reducing helium leak rates and providing cost savings by extending the operational life of the chucks up to 20 times compared to traditional designs.
Implementation Method 1
The protective cover may include a plasma resistant ceramic portion and a conductive portion
Implementation Method 2
The conductive portion enables the protective cover to be secured (e.g., chucked) by the electrostatic chuck
Implementation Method 3
a heat conductive fluid such as helium gas is pumped into an interface between the electrostatic chuck and the supported substrate
Data Source
AI summary
A protective cover for an electrostatic chuck may include a conductive wafer and a plasma resistant ceramic layer on at least one surface of the conductive wafer. The plasma resistant ceramic layer covers a top surface of the conductive wafer, side walls of the conductive wafer and an outer perimeter of a bottom surface of the conductive wafer. Alternatively, a protective cover for an electrostatic chuck may include a plasma resistant bulk sintered ceramic wafer and a conductive layer on a portion of a bottom surface of the plasma resistant bulk sintered ceramic wafer, wherein a perimeter of the bottom surface is not covered. The protective layer may be used to protect an electrostatic chuck during a plasma cleaning process.