Electrostatic Chuck Neutralization Circuit for Residual Charge Release
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Solution Overview
Problem
In electrostatic chucks used in semiconductor manufacturing, residual charges can cause substrates to remain attracted due to leakage currents from embedded heaters, even after the power supply is stopped, leading to incomplete neutralization and substrate retention issues.
Innovation Solution
The electrostatic attraction device incorporates a DC power source unit with a first neutralizing circuit that connects and disconnects the electrode to ground via a voltage-drop resistance and a second neutralizing circuit with an isolation relay, allowing for complete discharge of charges without resistance, ensuring the electrode is properly neutralized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single neutralizing circuit with ground relay is used, then the device complexity is reduced, but the neutralization completeness deteriorates due to residual charges from leakage currents
Solution Approach 1:
The neutralizing circuit is divided into two separate circuits: a first neutralizing circuit with a first ground relay and voltage-drop resistance, and a second neutralizing circuit with a second ground relay and no resistance. This segmentation allows each circuit to perform a specific neutralization function, achieving complete charge discharge while maintaining manageable complexity through modular design.
Solution Approach 2:
The isolation relay acts as an intermediary component that controls the switching between the first and second neutralizing circuits. It enables sequential activation of the two neutralizing paths, ensuring that both circuits can be utilized without direct interference, thereby achieving complete neutralization while keeping the overall circuit architecture organized and controllable.
2Reliability
If voltage-drop resistance is used in the neutralizing circuit, then the circuit safety is improved, but the charge discharge speed deteriorates due to resistance limitation
Solution Approach 1:
The discharge path is segmented into two parallel routes: one through the voltage-drop resistance (first neutralizing circuit) for safe, controlled discharge, and another without resistance (second neutralizing circuit) for rapid charge elimination. This segmentation allows the system to simultaneously achieve both safety and speed requirements.
Solution Approach 2:
The system dynamically switches between the first and second neutralizing circuits using isolation relay control. The second ground relay is activated only after the first neutralizing circuit has performed initial discharge, creating a dynamic two-stage discharge process that optimizes both safety and discharge speed at different time points.
3Speed
If the ground relay connects electrode to ground directly without resistance, then the neutralization speed is improved, but the risk of discharge sparks and damage increases
Solution Approach 1:
The first neutralizing circuit with voltage-drop resistance is activated first to perform preliminary charge discharge, reducing the charge level to a safe threshold before the second neutralizing circuit without resistance is activated. This preliminary action eliminates the harmful discharge spark risk when using the high-speed second circuit.
Solution Approach 2:
The neutralizing function is segmented into two sequential stages: the first stage uses resistance-based safe discharge, and the second stage uses resistance-free rapid discharge. This segmentation ensures that the harmful effects are avoided in the first stage, enabling the second stage to operate at high speed without risk.
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 effectively prevents electrode charge-up and substrate attraction when leakage currents occur, ensuring reliable neutralization and substrate release during power supply cessation.
Implementation Method 1
a first ground relay that connects and disconnects the electrode and the ground via a voltage-drop resistance member
Implementation Method 2
an object to be attracted is attracted by an electrostatic force when a DC voltage is applied to the electrode
Implementation Method 3
a second ground relay that is connected to a power supply path between the isolation relay and the electrode and connects and disconnects the electrode and the ground side without going through a resistance member
Data Source
AI summary
There is provided an electrostatic attraction device having an electrostatic chuck in which an electrode and a heater are embedded in a dielectric. The device comprises: a DC power source unit having a DC power source configured to supply a DC power to the electrode; a first neutralizing circuit connected to a power supply path between the DC power source and the electrode; and a second neutralizing circuit connected to a power supply path between the first neutralizing circuit and the electrode. The first neutralizing circuit has a first ground relay that connects and disconnects the electrode and the ground via a voltage-drop resistance member, and the second neutralizing circuit has an isolation relay that connects and disconnects the first neutralizing circuit and the second neutralizing circuit, and a second ground relay that is connected to a power supply path between the isolation relay and the electrode and connects and disconnects the electrode and the ground side without going through a resistance member.