Electrostatic Chuck Bias Layout for Edge Ion Angle Control
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Solution Overview
Problem
Existing plasma processing technologies face challenges in controlling the ion incidence angle at the edge portions of substrates, leading to variations in plasma processing results such as etching rates and film hole roundness.
Innovation Solution
A plasma processing apparatus is designed with an electrostatic chuck that includes a substrate bias electrode and an edge ring bias electrode, where the edge ring bias electrode has an annular overlapping portion with the substrate bias electrode, and the width of this overlapping portion is optimized to 9 mm to 11 mm, allowing for controlled ion incidence angles through adjustable potential differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional plasma processing is used without optimized electrode configuration, then the structure is simple, but the ion incidence angle at edge portions cannot be controlled precisely
Solution Approach 1:
The bias electrode is segmented into a central substrate bias electrode and an annular edge ring bias electrode with a specific overlapping portion. This segmentation allows independent control of electric bias for the substrate center and edge portions, enabling precise control of ion incidence angles at different locations without requiring complete restructuring of the electrode system.
Solution Approach 2:
The edge ring bias electrode is configured with a specific overlapping width (9-11 mm) relative to the substrate bias electrode, creating localized electric field distribution. This local quality optimization ensures that the ion incidence angle at the edge portions can be controlled independently from the center, achieving precise angular control where needed without affecting the overall system excessively.
2Reliability
If edge ring wears out in conventional systems, then continuous operation is possible, but plasma processing results such as etching rates and film hole roundness vary
Solution Approach 1:
The system dynamically adjusts the electric bias applied to the edge ring bias electrode independently from the substrate bias electrode. Even when the edge ring wears out, the dynamic control capability allows compensation for changes in electrical characteristics, maintaining stable ion incidence angles and consistent plasma processing results throughout the edge ring's extended service life.
Solution Approach 2:
The independent bias control system provides feedback capability where the electric bias to the edge ring bias electrode can be adjusted based on processing results. This allows compensation for edge ring wear effects, maintaining stable etching rates and film hole roundness even as the edge ring deteriorates over time.
3Manufacturing precision
If phase difference between substrate bias and edge ring bias is not controlled, then electrode configuration is simple, but plasma processing uniformity deteriorates
Solution Approach 1:
The bias control system dynamically adjusts the timing and magnitude of voltage pulses applied to both the substrate bias electrode and edge ring bias electrode. This dynamic control enables precise management of phase differences between the two biases, ensuring uniform plasma processing by coordinating ion acceleration timing across different substrate regions without requiring overly complex hardware.
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 ion incidence angle at the edge portions of substrates, thereby stabilizing plasma processing results such as etching rates and film hole roundness, even when the edge ring wears out.
Implementation Method 1
an electrostatic chuck disposed on the conductive base and having a substrate support surface and an edge ring support surface, an edge ring disposed on the edge ring support surface
Implementation Method 2
a first voltage pulse generator electrically connected to the substrate bias electrode and configured to generate a sequence of first voltage pulses having a first voltage level; and a second voltage pulse generator electrically connected to the edge ring bias electrode and configured to generate a sequence of second voltage pulses having a second voltage level
Data Source
AI summary
A plasma processing apparatus is provided with: a chamber; a substrate support disposed inside the chamber and including a conductive base, an electrostatic chuck having a substrate support surface and an edge ring support surface, an edge ring disposed on the edge ring support surface, a substrate bias electrode disposed below the substrate support surface, and an edge ring bias electrode disposed below the edge ring support surface; an upper electrode disposed above the substrate support; a radio frequency (RF) generator electrically connected to the conductive base and configured to generate an RF signal; a first voltage pulse generator electrically connected to the substrate bias electrode and configured to generate a sequence of first voltage pulses having a first voltage level; and a second voltage pulse generator electrically connected to the edge ring bias electrode and configured to generate a sequence of second voltage pulses having a second voltage level.