RF Heater Power Cable With Isolation for Resonance Compensation
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Solution Overview
Problem
In substrate processing systems, the impedance shift caused by heating elements in the electrode and edge ring leads to local resonances, impairing the RF generating system, reducing etch rates, and causing wafer non-uniformity.
Innovation Solution
A combined heater and filter system with a single power delivery cable and an RF blocking or isolation device, such as an inductor, is used to compensate for impedances, shifting the resonance frequency and minimizing interference with the RF generating system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heating elements are added to the edge ring and electrode, then substrate processing capability is improved, but impedance shift and local resonances occur that impair RF generating system
Solution Approach 1:
An isolation device is introduced as an intermediary component between the heating elements and the RF generating system. This isolation device acts as a mediator that blocks or filters the harmful impedance shifts and resonance frequencies from propagating back to the RF generating system, while still allowing the heating elements to function properly for substrate processing.
Solution Approach 2:
The patent converts the harmful resonance frequencies and impedance shifts into a beneficial configuration by designing the isolation device to specifically target and neutralize these frequencies. The isolation device uses the known resonance characteristics to design filters or dampers that transform the problematic electromagnetic interactions into stable operating conditions.
2Temperature
If heating elements are used in the electrode, then wafer heating is achieved, but power loss increases due to resonance frequencies
Solution Approach 1:
The isolation device serves as an intermediary that separates the heating function from the RF power delivery system. It allows thermal energy to be effectively delivered to the wafer while blocking the reverse flow of electromagnetic energy that would otherwise cause power loss through resonance.
3Reliability
If multiple separate cable systems are used for edge ring and electrode heating, then power delivery is reliable, but device complexity increases
Solution Approach 1:
The patent combines multiple separate cable systems into a single integrated cable assembly that delivers power to both the edge ring and electrode heating elements. This unified approach reduces the number of separate connections and components while maintaining reliable power delivery to all heating elements through the shared isolation device.
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 solution effectively reduces power loss and maintains optimal RF power delivery, improving etch rates and wafer uniformity by canceling or shifting resonance frequencies.
Implementation Method 1
The isolation device is configured to compensate for a resonance frequency generated during operation of the edge ring and the one or more heating elements
Implementation Method 2
The isolation device includes an inductor. The inductor is air wound. The inductor is formed around an inductor core.
Implementation Method 3
The isolation device includes at least one of a ferrite bead and ferrite bead material.
Data Source
AI summary
A substrate support includes an edge ring, one or more heating elements, and a cable configured to provide power from a power source to the edge ring and the one or more heating elements. The cable includes a first plurality of wires connected to the edge ring, a second plurality of wires connected to the one or more heating elements, a filter module, wherein the first plurality of wires and the second plurality of wires are twisted together within the filter module, and an isolation device. The isolation device is connected to the first plurality of wires and disposed between the filter module and the edge ring. The isolation device is configured to compensate for a resonance frequency generated during operation of the edge ring and the one or more heating elements.