Substrate Treatment Apparatus Filter Circuit for DC Power Protection
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Solution Overview
Problem
Existing substrate treatment apparatuses face damage to high voltage DC power supplies due to AC power usage, particularly in electrostatic chucks, which are essential for substrate attraction during plasma treatment.
Innovation Solution
A substrate treatment apparatus is designed with a dual AC power supply system and a filter circuit that differentiates between high radio frequency (HRF) and low radio frequency (LRF) AC power, ensuring low impedance for HRF and high impedance for LRF, thereby protecting the DC power supply from AC power interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC power is supplied to the upper electrode for plasma generation, then plasma treatment can be performed, but the AC power may cause damage to the high voltage DC power supply
Solution Approach 1:
The power supply system is segmented into separate AC power supplies for plasma generation and DC power supply for the electrostatic chuck, with a filter circuit blocking AC power from reaching the DC power supply. This segmentation protects the DC power supply while maintaining plasma generation capability.
Solution Approach 2:
A filter circuit acts as an intermediary between the AC power supply and DC power supply, blocking harmful AC power while allowing the DC power supply to function normally. The filter circuit includes capacitors and inductors that create frequency-dependent impedance to protect the DC power supply.
2Reliability
If a filter circuit is added to protect the DC power supply from AC power, then the DC power supply is protected, but the device complexity increases
Solution Approach 1:
The filter circuit uses frequency-dependent impedance characteristics where capacitors present low impedance to high-frequency AC power and high impedance to low-frequency or DC signals. This dynamic impedance behavior automatically protects the DC power supply without requiring complex active control circuits.
3Reliability
If dual AC power supplies with different frequencies are used for plasma generation, then plasma treatment effectiveness is improved, but the risk of AC power interference with DC power supply increases
Solution Approach 1:
The filter circuit is designed with different impedance characteristics for different frequency components. Capacitors provide low impedance paths for high-frequency AC power while presenting high impedance to lower frequency signals, allowing selective filtering of harmful AC components while maintaining plasma generation effectiveness.
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 allows for effective plasma generation between electrodes while safeguarding the DC power supply, reducing substrate warpage and maintaining apparatus efficiency without increasing size, thus protecting the electrostatic chuck from AC power damage.
Implementation Method 1
the filter circuit includes a first filter circuit that becomes low impedance with respect to AC power at the first frequency compared to AC power at the second frequency, and a second filter circuit that becomes low impedance with respect to AC power at the second frequency compared to AC power at the first frequency
Implementation Method 2
a high voltage DC power supply that applies a voltage to the lower electrode to suck the substrate to the lower electrode using an electrostatic chuck
Implementation Method 3
generate plasma between a lower electrode and an upper electrode by supplying AC power to the upper electrode while supplying a material gas to between the lower electrode and the upper electrode
Data Source
AI summary
A substrate treatment apparatus includes a lower electrode, an upper electrode, a first AC power supply that is connected to the upper electrode and supplies AC power at a first frequency, a second AC power supply that is connected to the upper electrode and supplies AC power at a second frequency which is lower than the first frequency, an internal electrode provided in the lower electrode, a filter circuit connected to the internal electrode, and a DC power supply connected to the internal electrode via the filter circuit. The filter circuit includes a first filter circuit that becomes low impedance with respect to AC power at the first frequency compared to AC power at the second frequency, and a second filter circuit that becomes low impedance with respect to AC power at the second frequency compared to AC power at the first frequency.