Segmented Ground Electrodes for Plasma Uniformity in Substrate Processing
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Solution Overview
Problem
As substrate sizes increase, localized variations in plasma density lead to non-uniform thin film properties and thickness uniformity issues at the center and edge portions, due to plasma density non-uniformity.
Innovation Solution
A substrate processing apparatus with a power supply unit, processing unit, and substrate support unit featuring multiple ground electrodes, including a disk-shaped and ring-shaped electrode configuration, connected to an L-C circuit for independent plasma intensity control, which adjusts plasma density and intensity through parameter control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single ground electrode is used in the substrate support unit, then the device complexity is low, but plasma density uniformity deteriorates at the center and edge portions of the substrate
Solution Approach 1:
The ground electrode is divided into multiple segments (first ground electrode and second ground electrode) arranged at different radial positions. This segmentation allows independent control of plasma density at different locations, resolving the uniformity issue while maintaining manageable complexity through modular design
Solution Approach 2:
Different ground electrodes are positioned to provide different electrical characteristics at different radial positions (center vs. edge). The first ground electrode addresses center region plasma density while the second ground electrode addresses edge region plasma density, applying local quality adjustment to achieve overall uniformity
2Manufacturing precision
If multiple ground electrodes are added to control plasma uniformity, then plasma density uniformity improves, but the device complexity increases
Solution Approach 1:
The substrate support unit's ground electrode system is segmented into multiple independent electrodes, each controllable through separate plasma intensity controllers. This enables precise control of thin film thickness uniformity while managing complexity through functional modularity
Solution Approach 2:
Plasma intensity controllers adjust electrical parameters (power, frequency) of each ground electrode independently to optimize plasma density distribution. This parameter control approach achieves uniform thin film deposition without requiring complex mechanical or structural modifications
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
This configuration effectively reduces plasma non-uniformity, improving thin film properties and thickness uniformity across the substrate by allowing individual control of plasma at the center and edge regions.
Implementation Method 1
at least one of the first ground electrode and the second ground electrode is connected to an L-C circuit including an inductor, a capacitor, and a variable capacitor
Implementation Method 2
the processing unit may be configured to function as an electrode that supplies power to a reaction space
Data Source
AI summary
A substrate processing apparatus capable of locally controlling a plasma intensity and improving thin film properties and thickness uniformity includes: a power supply unit, a processing unit electrically connected to the power supply unit, and a substrate support unit below the processing unit, wherein the substrate support unit includes a first ground electrode and a second ground electrode.