Electrostatic Chuck Electrode Layout for Uniform Plasma Wafer Clamping
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in efficiently and uniformly attracting substrates and edge rings using electrostatic chucks, particularly due to issues with residual attraction caused by water molecules and non-uniform electric fields.
Innovation Solution
The plasma processing apparatus employs a dielectric member with phase-shifted AC voltages applied to multiple chuck electrodes arranged in a spiral or nested structure, which enhances the attraction force and uniformity by minimizing residual attraction from water molecules and optimizing electric potential distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single electrode configuration is used in the electrostatic chuck, then the device complexity is low, but the attraction force uniformity is insufficient
Solution Approach 1:
The electrostatic chuck electrode is divided into multiple independent electrodes (first electrode, second electrode, third electrode, fourth electrode) arranged in a specific pattern. Each electrode can be independently controlled to create a more uniform electric field distribution across the substrate surface, thereby improving attraction force uniformity while managing device complexity through modular design
Solution Approach 2:
Different regions of the electrostatic chuck are equipped with different electrode configurations tailored to local requirements. The first and second electrodes are positioned to address specific zones, creating locally optimized electric fields that collectively achieve uniform overall attraction force across the substrate
2Force
If DC voltage is applied to the electrostatic chuck electrode, then the attraction force is strong, but residual attraction from water molecules occurs
Solution Approach 1:
The electrostatic chuck applies periodic AC voltage to the electrode instead of continuous DC voltage. This periodic action creates oscillating electric fields that prevent water molecules from forming stable dipole alignments, thereby eliminating residual attraction while maintaining sufficient attraction force through the time-averaged effect of the AC voltage
Solution Approach 2:
The voltage parameter is changed from DC to AC with specific frequency and amplitude characteristics. This parameter change transforms the electric field behavior to prevent water molecule polarization and residual attraction, while the AC voltage magnitude is controlled to maintain adequate attraction force for substrate processing
3Manufacturing precision
If multiple electrodes with phase-shifted AC voltages are used, then the attraction force uniformity is improved, but the device complexity increases
Solution Approach 1:
The electrode system is segmented into multiple independently controllable electrodes, each receiving phase-shifted AC voltages. This segmentation enables precise control of electric field distribution across different substrate regions, achieving uniform attraction force while the modular structure helps manage system complexity
Solution Approach 2:
The electrode system employs dynamic phase-shifted AC voltages that can be adjusted in real-time. This dynamic control allows the system to adapt to different processing conditions and maintain uniform attraction force, while the phased approach to voltage application provides a systematic method for managing control complexity
4Object-generated harmful factors
If the electrostatic chuck uses a simple electrode arrangement, then the device complexity is low, but the residual attraction from water molecules is not minimized
Solution Approach 1:
The electrode configuration employs periodic AC voltage application with specific frequency characteristics that prevent water molecule polarization. This periodic action effectively minimizes residual attraction while the electrode arrangement is designed to work synergistically with the voltage timing to achieve this effect without excessive complexity
Solution Approach 2:
The electrode configuration is designed to create equipotential regions that minimize electric field gradients which could cause water molecule alignment and residual attraction. By carefully positioning multiple electrodes and applying phase-shifted voltages, the system achieves uniform potential distribution that reduces harmful residual effects
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 improves the attraction force and uniformity of substrate and edge ring attachment, reducing residual attraction and ensuring consistent processing performance.
Implementation Method 1
an electrostatic chuck disposed in the plasma processing chamber, the electrostatic chuck including a dielectric member including a substrate support surface and a ring support surface, a plurality of chuck electrodes disposed under the substrate support surface in the dielectric member
Implementation Method 2
AC voltages being phase-shifted relative to each other. The plurality of chuck electrodes disposed under the ring support surface include one chuck electrode and another chuck electrode
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber; an electrostatic chuck disposed in the plasma processing chamber, the electrostatic chuck including a dielectric member including a substrate support surface and a ring support surface, and chuck electrodes disposed under the substrate support surface and the ring support surface in the dielectric member; and an alternating current voltage generator that applies AC voltages to the chuck electrodes disposed under the ring support surface, the AC voltages being phase-shifted relative to each other. The chuck electrodes disposed under the ring support surface include one chuck electrode and another chuck electrode that include arc portions. The arc portions of the one chuck electrode and the another chuck electrode are arranged alternately in a radial direction. The chuck electrodes disposed under the substrate support surface have a spiral shape and the chuck electrodes disposed under the ring support surface have a nested structure.