Electrostatic Chuck Electrode Layout for Focus Ring Wear Control
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Solution Overview
Problem
The electrostatic chuck device experiences a decrease in focus ring thickness over time, leading to changes in plasma capacity and uniformity, resulting in etching rate differences and increased wear, particularly between the center and outer peripheral portions of the wafer.
Innovation Solution
The device incorporates a dielectric substrate with first and second electrodes connected via power wires and current regulators, allowing for controlled current flow to the focus ring, using constant current circuits to maintain plasma uniformity and prevent excessive power input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the focus ring is used continuously without additional electrodes, then the device structure remains simple, but the plasma uniformity deteriorates as the focus ring thickness decreases
Solution Approach 1:
The electrode structure is segmented into a first electrode for the wafer and a second electrode for the focus ring. This segmentation allows independent control of plasma parameters for each region, maintaining plasma uniformity even as the focus ring wears down, without significantly increasing overall structural complexity.
Solution Approach 2:
Different regions are given different electrode structures: the first electrode region controls plasma for the wafer while the second electrode region controls plasma for the focus ring. This local differentiation enables precise plasma uniformity control in the focus ring area without affecting the overall device simplicity.
2Device complexity
If no current regulator is used, then the power connection is simple, but the etching rate uniformity deteriorates due to uncontrolled power input
Solution Approach 1:
A current regulator is introduced into the power connection to provide feedback control of the current supplied to the second electrode. This ensures that power input to the focus ring region is controlled, maintaining uniform etching rates even as the focus ring thickness changes during use.
3Ease of operation
If the focus ring thickness decreases over time, then no additional maintenance is needed, but the plasma capacity changes causing non-uniform plasma
Solution Approach 1:
The system dynamically adapts to changing focus ring thickness through the current regulator, which adjusts the current to the second electrode based on real-time conditions. This dynamic control compensates for wear-induced changes in plasma capacity, maintaining plasma uniformity without requiring maintenance or replacement of the focus ring.
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 plasma distribution around the focus ring, reducing etching rate differences and wear, thereby maintaining uniform plasma treatment across the wafer.
Implementation Method 1
an electrostatic chuck plate which has a dielectric substrate having a placement surface on which a wafer is placed and electrodes which are positioned in the dielectric substrate
Implementation Method 2
The power connection portion includes a power wire which electrically connects the first electrode and the second electrode via a current regulator
Data Source
AI summary
Provided is an electrostatic chuck device including: an electrostatic chuck plate which has a dielectric substrate having a placement surface on which a wafer is placed and electrodes positioned in the dielectric substrate; a focus ring which is installed on an outer peripheral portion of the electrostatic chuck plate and surrounding the placement surface; and a power connection portion which connects the electrode and a power supply. The electrostatic chuck plate has a first electrode positioned in a region overlapping the placement surface in plan view and a second electrode positioned in a region overlapping the focus ring in plan view. The power connection portion includes a power wire electrically connecting the first electrode and the second electrode via a current regulator.