Electrostatic Chuck Floating Power Supply Layout for Arc Reduction
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Solution Overview
Problem
Current semiconductor processing systems face challenges with current arcs, which are undesirable electrical discharges that can cause device damage, reduced yields, and increased manufacturing costs, despite existing mitigation techniques failing to completely eliminate arcing.
Innovation Solution
Implementing floating power supplies for electrostatic chucks that are electrically isolated from the system ground, creating a single current path between electrodes to balance current and eliminate free paths to the system ground, thereby reducing the likelihood of current arcs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional grounded power supplies are used for electrostatic chucks, then the system provides stable reference potential, but current arcs can occur between electrodes and system ground
Solution Approach 1:
The power supply system is segmented into isolated positive and negative power sources, each independently referenced to system ground through filter circuits. This segmentation prevents direct current paths between electrodes and ground, eliminating arc formation while maintaining stable electrostatic fields for substrate clamping.
Solution Approach 2:
Filter circuits serve as intermediary components between the floating power supplies and system ground. These intermediaries provide RF grounding while blocking DC current paths, allowing the power supplies to float at potentials that prevent arcing while maintaining compatibility with RF plasma processes.
2Reliability
If floating power supplies are implemented, then current arc paths are eliminated, but RF grounding compatibility becomes challenging
Solution Approach 1:
Filter circuits act as intermediaries that reconcile the floating power supply architecture with RF grounding requirements. The filters allow RF signals to reference system ground while blocking DC current paths, enabling simultaneous arc reduction and RF compatibility.
Solution Approach 2:
The system changes the electrical reference parameter of the power supplies from fixed ground reference to floating reference with RF coupling. This parameter change allows the power supplies to adapt to RF plasma environments while maintaining arc-free operation through dynamic potential adjustment.
3Reliability
If separate positive and negative power sources are used, then current balance between electrodes is improved, but system complexity increases
Solution Approach 1:
The power supply system is divided into separate positive and negative sources, each independently controlled and referenced. This segmentation enables precise current balance adjustment for each electrode while maintaining overall system stability through individual filter circuit grounding.
Solution Approach 2:
The system employs feedback control through the filter circuits that monitor and adjust the floating potentials of the power supplies. This feedback mechanism maintains balanced current distribution between electrodes while adapting to process conditions, preventing arcing without requiring complex direct control systems.
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 significantly reduces the risk of current arcs, maintaining compatibility with RF sources and ensuring stable electrostatic clamping forces, even at high temperatures, thus enhancing manufacturing efficiency and product quality.
Implementation Method 1
The semiconductor processing chamber may additionally include a filter circuit that may be electrically connected to the first electrode, the RF ground, and the first power source for the ESC. The filter circuit may electrically isolate the first power source for the ESC from the RF ground.
Implementation Method 2
The pedestal may include a first electrode and a second electrode for a electrostatic chuck (ESC).
Data Source
AI summary
Electrostatic chucks are used to provide a clamping force between the substrate and the pedestal during semiconductor processes. However, charge buildup on the chuck electrodes and/or the substrate may cause damaging current arcs to occur as excess charge finds new pathways to the system ground. This technology uses floating power sources for the electrostatic chuck that are electrically isolated from the system ground. The power sources for the positive and negative electrodes in the pedestal may be connected together, and the typical ground connection between the power supplies can be removed. Floating and connected power supplies create a single current path that balances current between the two electrodes and eliminates free current paths to the system ground. This greatly reduces the likelihood of current arcs from the electrostatic chuck.