Hydrophobic Substrate Support Unit for Plasma Processing Dew Control
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Solution Overview
Problem
Dew condensation occurs in plasma processing apparatuses due to the cooling of substrate support units, leading to reliability issues as moisture forms on components, compromising the integrity of the semiconductor process.
Innovation Solution
A substrate support unit is designed with an electrostatic chuck, insulating isolation unit, and ground plate, spaced apart to form an air gap, where the surfaces have hydrophobic properties, and a refrigerant or clean dry air is circulated to prevent dew condensation, reducing the risk of moisture accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate support unit is cooled by circulating refrigerant to maintain substrate temperature, then the substrate temperature control is improved, but dew condensation occurs on the substrate support unit and surrounding components
Solution Approach 1:
An insulating isolation unit is introduced as an intermediary component between the electrostatic chuck and the ground plate. This isolation unit prevents direct thermal conduction while maintaining electrical grounding, thereby reducing the temperature of surrounding components and minimizing dew condensation without compromising substrate temperature control
Solution Approach 2:
The patent applies different surface treatments to different components: the electrostatic chuck maintains its cooling function while the insulating isolation unit and ground plate are treated with hydrophobic coatings. This localized quality differentiation allows each component to address specific aspects of the dew condensation problem while maintaining their primary functions
2Temperature
If the substrate support unit temperature is reduced for cooling, then substrate overheating is prevented, but the reliability of the plasma processing apparatus decreases due to moisture formation
Solution Approach 1:
The patent changes the surface property parameter of the insulating isolation unit and ground plate by applying hydrophobic treatments. This parameter change increases the contact angle of water droplets, preventing moisture accumulation and thereby maintaining apparatus reliability even when the substrate support unit is cooled to low temperatures
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 hydrophobic treatment of surfaces in the substrate support unit significantly reduces dew condensation, enhancing the reliability of the plasma processing apparatus by minimizing moisture on components and potentially lowering the required flow rate of dry air for moisture removal.
Implementation Method 1
a lower surface of the electrostatic chuck, a surface of the insulating isolation unit, or a surface of the ground plate has hydrophobicity
Implementation Method 2
the substrate is cooled by circulating a refrigerant having a temperature lower than the room temperature in the substrate support unit
Data Source
AI summary
Provided is a substrate support unit including an electrostatic chuck configured to fix a wafer, an insulating isolation unit, which is arranged below the electrostatic chuck and is configured to insulate the electrostatic chuck, and a ground plate arranged below the insulating isolation unit, wherein the electrostatic chuck, the insulating isolation unit, and the ground plate are spaced apart from each other in a vertical direction, and a lower surface of the electrostatic chuck, a surface of the insulating isolation unit, or a surface of the ground plate has hydrophobicity.