Electrostatic Chuck Coating for Charge Trap and Wear Protection
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Solution Overview
Problem
Electrostatic Chucks (ESCs) face issues with charge traps and reduced clamping force due to fluorine exposure and residual carbon, which conventional Protective Electrostatic Covers (PECs) attempt to address but introduce complexity and maintenance challenges.
Innovation Solution
A method involving a coating of silicon oxide (SiO2) or silicon nitride (Si3N4) on the chucking surface of ESCs, which can be readily deposited and removed in situ within a processing chamber, protecting against wear and contamination, and improving clamping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Protective Electrostatic Cover (PEC) is used to protect the chucking surface, then the ESC is protected from fluorine exposure and carbon contamination, but the device complexity increases and maintenance becomes more challenging
Solution Approach 1:
The patent extracts the protective function from a separate PEC component and integrates it directly into the chucking surface through dielectric coating layers. This eliminates the need for removable covers while maintaining protection from fluorine exposure and carbon contamination, thereby reducing device complexity and maintenance burden.
Solution Approach 2:
The protective dielectric coating is merged with the chucking surface structure itself, combining the electrostatic clamping function and the protective function into a single integrated component. This eliminates the need for separate protective covers and simplifies the overall device architecture.
2Productivity
If the chucking surface is exposed to fluorine and residual carbon during substrate processing, then the processing can proceed, but charge traps form and clamping force decreases
Solution Approach 1:
The patent applies protective dielectric coatings to the chucking surface before substrate processing begins. This preliminary protective action prevents fluorine exposure and carbon contamination from forming charge traps, thereby maintaining clamping force throughout the processing cycle without interrupting productivity.
Solution Approach 2:
The dielectric coating acts as an intermediary layer between the chucking surface and the harmful environment (fluorine and carbon). This intermediate protective layer allows substrate processing to proceed while preventing the formation of charge traps that would reduce clamping force.
3Temperature
If the ESC operates at high temperatures, then substrate processing can be performed, but thermal expansion differences cause shear forces that wear the chucking surface
Solution Approach 1:
The patent applies hard dielectric coatings to the chucking surface before high-temperature processing begins. This beforehand protective cushioning prevents wear from shear forces caused by thermal expansion differences, thereby extending the operational life of the chucking surface while maintaining the ability to process substrates at high temperatures.
Solution Approach 2:
The patent uses composite dielectric coating structures (such as silicon oxide and silicon nitride layers) on the chucking surface. These composite materials provide both thermal stability for high-temperature processing and wear resistance against shear forces from thermal expansion differences, thereby extending component life.
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 silicon oxide and silicon nitride coating enhances electrostatic clamping force by preventing charge traps and carbon contamination, reducing maintenance complexity and extending the life of ESCs.
Implementation Method 1
ESCs operate by applying a charge of one polarity onto a chucking surface and a charge of the opposite polarity on a substrate. Since opposite charges attract, the substrate is held or clamped in place by the resulting electrostatic force.
Implementation Method 2
a method for (a) using a halogen-based cleaning agent to remove a first coating formed on a chucking surface of an ESC pedestal
Implementation Method 3
a coating of silicon oxide and/or silicon nitride is then typically applied to the clean surfaces in a subsequent plasma deposition step
Implementation Method 4
The coating can be used to protect the chucking surface from degradation and wear due to the shear lateral forces caused by different rates of thermal expansion between substrates and the chucking surface.
Data Source
AI summary
An ElectroStatic Chuck (ESC) including a chucking surface having at least a portion covered with a coating of silicon oxide (SiO2), silicon nitride (Si3N4) or a combination of both. The coating can be applied in situ a processing chamber of a substrate processing tool and periodically removed and re-applied in situ to create fresh coating.