Focus Ring Segmentation for Edge Etching Control
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Solution Overview
Problem
In plasma etching processes, controlling the etching rate at the edge region of a substrate while minimizing its impact on the central region is challenging due to the uniformity and efficiency requirements in manufacturing electronic devices.
Innovation Solution
A plasma processing apparatus with a focus ring having distinct regions, where the inner top surface has a higher negative DC bias potential than the outer top surface, allowing for independent control of the etching rate by adjusting the DC bias potential, thereby isolating the effects on the edge and central regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform DC bias potential is applied to the entire focus ring, then the etching process is simple to control, but the etching rate cannot be independently controlled at the edge region versus the central region
Solution Approach 1:
The focus ring is divided into multiple independent regions (first region and second region) with different DC bias potentials. The first region has a higher negative DC bias potential than the second region, enabling independent control of etching rates at different radial positions on the substrate. This segmentation allows precise control of edge region etching while maintaining central region etching characteristics.
Solution Approach 2:
Different regions of the focus ring are assigned different electrical properties (DC bias potentials) to achieve different etching characteristics in specific areas. The first region applies a higher negative DC bias potential to control etching at the substrate edge, while the second region applies a lower potential to maintain etching at the substrate center, creating local quality variations in the etching process.
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 enables precise control of the etching rate at the edge region while maintaining the etching rate in the central region, enhancing the uniformity and efficiency of the plasma etching process.
Implementation Method 1
The focus ring is configured such that an absolute value of a negative DC bias potential in the first region becomes greater than an absolute value of a DC potential in the second region during plasma generation in the chamber
Implementation Method 2
A radio-frequency power supply is electrically coupled to the lower electrode... during plasma generation in the chamber
Data Source
AI summary
An apparatus of plasma processing includes a substrate support and a focus ring that are arranged in a chamber. The focus ring surrounds a substrate on the substrate support. The focus ring has a first region and a second region. The first region includes an inner top surface of the focus ring. The second region includes an outer top surface of the focus ring. The inner top surface extends at a position closer to the central axis of the focus ring than the outer top surface. The focus ring is configured such that an absolute value of a negative DC bias potential in the first region becomes greater than an absolute value of a DC potential in the second region during plasma generation in the chamber.