Electrostatic Chuck Bias Electrode Layout for Abnormal Discharge Suppression
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Solution Overview
Problem
High-power radio-frequency ion drawing-in conditions in plasma processing can lead to abnormal discharges at the back surface of substrates and edge rings due to potential differences caused by capacitance between electrodes and substrates/edge rings, resulting in inefficient plasma processing and potential damage.
Innovation Solution
Incorporation of bias electrodes within the electrostatic chuck, specifically a bias electrode in the first region and another in the second region, to increase capacitance and reduce potential differences, thereby suppressing abnormal discharges by applying radio-frequency power to these electrodes, which are designed to match impedance and control ion drawing-in processes independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power radio-frequency is applied for ion drawing-in, then plasma processing efficiency is improved, but abnormal discharges occur at the back surface of substrates and edge rings
Solution Approach 1:
The electrostatic chuck is divided into multiple independent electrode regions: a first electrode for applying DC voltage to the substrate, a second electrode for applying DC voltage to the edge ring, and a third electrode for applying bias power. This segmentation allows independent control of potential differences in different regions, preventing abnormal discharges while maintaining high-power plasma processing efficiency.
Solution Approach 2:
Different regions of the electrostatic chuck are assigned different electrical characteristics and functions. The first electrode region is optimized for substrate potential control, the second electrode region for edge ring potential control, and the third electrode region for bias power application. This local differentiation enables precise control of ion drawing-in without causing abnormal discharges at specific locations.
2Reliability
If DC voltage is applied to control substrate and edge ring potential, then abnormal discharges are suppressed, but additional electrodes and control systems are required
Solution Approach 1:
The electrostatic chuck structure integrates multiple functions into a unified device. The first, second, and third electrodes are all part of the electrostatic chuck assembly, which simultaneously performs substrate holding, edge ring positioning, and plasma potential control. This multi-functionality reduces the need for separate control systems while maintaining reliable suppression of abnormal discharges.
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 solution effectively reduces potential differences and suppresses abnormal discharges, enhancing the control over plasma processing characteristics, such as etching rates and film forming rates, by increasing capacitance and reducing impedance, thus improving the stability and efficiency of plasma processing.
Implementation Method 1
an electrostatic chuck configured to support a substrate; a first electrode provided in the first region and configured to apply a DC voltage; a second electrode provided in the second region and configured to apply a DC voltage
Implementation Method 2
The plasma processing apparatus excites a gas supplied into a chamber by a radio-frequency power applied to a stage of the plasma processing apparatus to thereby generate plasma
Implementation Method 3
a third electrode configured to apply a bias power... to increase capacitance and reduce potential differences, thereby suppressing abnormal discharges by applying radio-frequency power to these electrodes
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber; a base disposed in the plasma processing chamber; an electrostatic chuck, disposed on the base, having a substrate support portion and an edge ring support portion on which an edge ring is disposed so as to surround a substrate; a first clamping electrode disposed in the substrate support portion; a first bias electrode disposed below the first clamping electrode in the substrate support portion; a second clamping electrode disposed in the edge ring support portion; a second bias electrode disposed below the second clamping electrode in the edge ring support portion; a first power source electrically connected to the first bias electrode; and a second power source electrically connected to the second bias electrode.