Substrate Support Circuit for Plasma Edge Uniformity Control
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in effectively controlling plasma density and uniformity, particularly at the edge of the substrate, which affects processing consistency and efficiency.
Innovation Solution
A plasma processing apparatus with a substrate support system that includes a conductive base, electrostatic chuck, substrate and ring electrodes, edge ring, RF generator, voltage pulse generator, and potential control circuit with variable impedance elements, allowing precise control of RF and pulsed voltage signals to maintain horizontal plasma sheaths and perpendicular ion incidence on the substrate edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing is used, then processing can be performed on the substrate, but plasma density uniformity at the substrate edge cannot be effectively controlled
Solution Approach 1:
The substrate support system is segmented into multiple independent electrodes: a substrate electrode for the central substrate region and a ring electrode for the edge region. This segmentation allows independent potential control of each region, enabling separate optimization of plasma density uniformity in different areas without requiring complete redesign of the entire processing system.
Solution Approach 2:
Different regions of the substrate are assigned different electrical potentials through the substrate electrode and ring electrode. The ring electrode specifically controls the edge region potential while the substrate electrode controls the central region, allowing local optimization of plasma density characteristics in each area to achieve overall uniformity.
2Manufacturing precision
If additional control circuits and variable impedance elements are added, then plasma density control is improved, but device complexity increases
Solution Approach 1:
Variable impedance elements are incorporated into the control circuits to dynamically adjust electrical parameters during plasma processing. This allows real-time optimization of plasma density control precision by adapting the control characteristics to changing process conditions, achieving high precision without requiring overly complex static control systems.
Solution Approach 2:
The control system utilizes variable impedance elements that can change electrical parameters such as resistance and capacitance. By dynamically adjusting these parameters in the control circuits connected to the substrate and ring electrodes, the system achieves precise plasma density control while keeping the overall device architecture relatively simple.
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 ensures consistent and efficient plasma processing by maintaining perpendicular ion incidence and uniform plasma density across the substrate, enhancing processing quality and efficiency.
Implementation Method 1
an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface
Implementation Method 2
an RF generator electrically connected to the conductive base and configured to generate an RF signal
Implementation Method 3
a voltage pulse generator electrically connected to the conductive base and configured to generate a pulsed voltage signal
Implementation Method 4
a potential control circuit electrically connected to the second conductor between the ring electrode and the conductive base, the potential control circuit including at least one variable impedance element
Data Source
AI summary
A plasma processing apparatus includes a chamber; a substrate support disposed in the chamber, the substrate support including a conductive base, an electrostatic chuck, a substrate electrode electrically connected to the conductive base via a first conductor, a ring electrode electrically connected to the conductive base via a second conductor, and an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; an RF generator electrically connected to the conductive base; a voltage pulse generator electrically connected to the conductive base; and a potential control circuit electrically connected to the second conductor between the ring electrode and the conductive base, the potential control circuit including at least one variable impedance element.