Modular Low-k RF Rod Assembly for High-Voltage Bias Delivery
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Solution Overview
Problem
Existing J-shaped RF rods in plasma chambers are expensive to manufacture, difficult to install and maintain, suffer from high capacitance, and cannot handle high voltages due to arcing issues.
Innovation Solution
A modular RF rod assembly with an L-shape and overmolded insulators, featuring a conductive bridge and air gaps to reduce capacitance, allowing for simpler construction and enabling higher voltage use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a J-shaped RF rod is used to route RF power laterally and vertically, then the RF power delivery path is established, but the manufacturing cost increases and installation/repair difficulty increases
Solution Approach 1:
The RF rod is divided into multiple straight segments (first rod, second rod) oriented at approximately ninety degrees to each other, replacing the traditional curved J-shape. This segmentation allows each component to be manufactured separately using simple processes and then assembled together, reducing manufacturing complexity while maintaining the L-shaped configuration for lateral and vertical power routing.
2Productivity
If a J-shaped RF rod is used to deliver RF power to the ESC, then the power delivery path is established, but the capacitance from power to ground increases, decreasing power delivery efficiency
Solution Approach 1:
An insulator is introduced as an intermediary material surrounding the RF rod assembly. This insulator acts as a mediator between the conductive RF rod and the ground, reducing the capacitive coupling between them. By placing this dielectric barrier, the capacitance from power to ground is reduced, thereby improving power delivery efficiency and reducing energy loss.
3Productivity
If higher voltages are used to overcome efficiency limitations, then power delivery efficiency improves, but arcing occurs at the J-shaped RF rod
Solution Approach 1:
The RF rod assembly uses a composite structure combining conductive elements (first rod, second rod, bridge) with insulating materials (insulator surrounding the assembly). This composite construction provides both electrical conductivity for power delivery and electrical insulation to prevent arcing. The insulator material with appropriate dielectric strength allows the system to operate at higher voltages (up to 10 kV) without experiencing arcing, thereby improving both efficiency and reliability.
4Ease of operation
If a J-shaped RF rod construction is used, then the lateral and vertical RF power routing is achieved, but the installation and repair processes become more difficult
Solution Approach 1:
The RF rod is segmented into separate straight components (first rod, second rod) that can be independently handled and installed. This segmentation transforms the complex curved J-shape into manageable straight sections that are easier to install, replace, and repair. The modular nature of the segmented construction allows for simpler maintenance operations while achieving the same L-shaped power routing function.
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 modular design simplifies manufacturing and maintenance, reduces capacitance, and allows for higher voltage operation up to 10 kV, improving electrical efficiency and preventing arcing.
Implementation Method 1
an interior surface of the housing is spaced away from the second insulator by an air gap
Implementation Method 2
a first insulator is over an outer surface of the inner rod assembly... a second insulator is provided over an outer surface of the shell
Data Source
AI summary
Embodiments described herein relate to an apparatus that includes an inner rod assembly. In an embodiment, the inner rod assembly includes a first rod and a second rod oriented approximately ninety degrees with respect to the first rod. In an embodiment, a bridge is electrically coupled to the first rod and the second rod. In an embodiment, a first insulator is over an outer surface of the inner rod assembly, and a shell is provided around the inner rod assembly. In an embodiment, a second insulator is provided over an outer surface of the shell, and a housing surrounds the shell. In an embodiment, an interior surface of the housing is spaced away from the second insulator by an air gap.