Replaceable Electrostatic Chuck Sidewall Shield for Plasma Etching
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Solution Overview
Problem
Electrostatic chucks in plasma etching processes deteriorate due to plasma etching and process kit installation/removal, leading to gas leakage, edge arcing, and contamination, with existing solutions like epoxy being permanent and ineffective against plasma damage.
Innovation Solution
A replaceable electrostatic chuck sidewall shield made of materials like perfluoroelastomers or fluorocarbons, which encircles the perimeter of the electrostatic chuck, providing enhanced resistance to plasma damage and allowing for easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy is applied to the ESC in areas prone to parts abrasion, then deterioration is slowed down, but the epoxy is not resistant to plasma damage and gas leakage and edge arcing continue to occur
Solution Approach 1:
The protective coating is divided into multiple functional layers: a bottom epoxy layer that provides adhesion and basic protection, and a top PTFE layer that provides plasma resistance. This segmentation allows each layer to specialize in its optimal function, resolving the contradiction between adhesion needs and plasma resistance.
Solution Approach 2:
The invention uses a composite material system combining epoxy and PTFE. The epoxy provides structural bonding and baseline protection, while the PTFE overlay provides superior plasma and chemical resistance. This composite approach allows the coating system to simultaneously achieve adhesion, plasma resistance, and abrasion resistance that neither material could achieve alone.
2Reliability
If epoxy is applied to the ESC, then deterioration is slowed down, but the application is permanent and makes refurbishment difficult
Solution Approach 1:
The protective coating is divided into multiple functional layers: a bottom epoxy layer that provides adhesion and basic protection, and a top PTFE layer that provides plasma resistance. This segmentation allows each layer to specialize in its optimal function, resolving the contradiction between adhesion needs and plasma resistance.
Solution Approach 2:
The PTFE overlay is designed as a consumable layer that can be removed and replaced when deteriorated, while the permanent epoxy substrate remains. This allows refurbishment by simply replacing the top layer rather than the entire coating system, making maintenance more economical and less complex.
3Productivity
If the ESC operates in plasma environment, then wafer processing is enabled, but plasma by-products cause ESC deterioration through plasma etching
Solution Approach 1:
The PTFE overlay acts as an intermediary protective layer between the ESC and the harsh plasma environment. It specifically resists fluorocarbon-based plasma by-products that would otherwise directly attack and etch the ESC surfaces, enabling continuous wafer processing without compromising ESC integrity.
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 replaceable sidewall shield significantly extends the life of electrostatic chucks by preventing gas leakage and edge arcing, maintaining heat transfer efficiency, and enabling cost-effective refurbishment.
Implementation Method 1
The plasma and plasma by-products may cause the ESC to deteriorate in a process known as plasma etching or process gas erosion.
Implementation Method 2
The ESC is a device that employs electricity to generate electrostatic forces, such as Coulombic and Johnson-Rahbek Forces, that hold the wafer in place in the plasma chamber
Implementation Method 3
The ESC is a device that employs electricity to generate electrostatic forces, such as Coulombic and Johnson-Rahbek Forces, that hold the wafer in place
Implementation Method 4
Many modern ESCs use a gas as a heat-conductive material. The gas is supplied through the ESC surface to transfer heat between the wafer and the ESC to control wafer temperature during the etching process.
Implementation Method 5
As these areas wear down, the heat transfer gas escapes without carrying heat away from the wafer
Implementation Method 6
electricity arcs between the internal components of the ESC, reducing the holding force of the ESC
Data Source
AI summary
A replaceable electrostatic chuck sidewall shield is provided. The replaceable electrostatic chuck sidewall shield fills or partially fills an indentation located between a base member and a top member of an electrostatic chuck, such that the replaceable electrostatic chuck sidewall shield may protect an epoxy in the indentation or may replace the epoxy within the indentation. The replaceable electrostatic chuck sidewall shield may be fully contained with the indentation. The replaceable electrostatic chuck sidewall shield may also cover an epoxy in the indentation such that the replaceable electrostatic chuck sidewall shield protrudes beyond the indentation. In an alternate embodiment, the replaceable electrostatic chuck sidewall shield substantially covers the area in which a conductive pole is embedded in a bipolar electrostatic chuck.