Triaxial RF DC Rod Assembly for Plasma Chamber Chuck
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Delivering RF power and DC voltage to a plasma processing chamber's chuck with a distinct clamping electrode is challenging due to ground arcing concerns, especially with increased power densities in modern plasma processing equipment.
Innovation Solution
A triaxial RF/DC rod assembly is used, featuring a center conductor for DC power, a concentric annular RF transmission line, and a ground plane conductor, all insulated from each other, to safely deliver power to a chuck with a DC biased, RF floating electrode and an RF powered electrode, separated from the ground by an insulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrode is embedded within the dielectric layer for both RF power and DC voltage delivery, then the chuck structure is simplified, but ground arcing concerns increase with increased power densities
Solution Approach 1:
The patent divides the single electrode function into two separate electrodes: an RF electrode for radio frequency power delivery and a DC electrode for direct current voltage delivery. This segmentation allows independent optimization of each electrode's function and reduces the risk of ground arcing by separating the high-voltage DC path from the RF path, thereby resolving the contradiction between structural simplicity and arcing reliability.
Solution Approach 2:
The patent introduces an insulator as an intermediary element between the RF electrode and the ground plane. This insulator mediates the electrical interaction, allowing the RF electrode to be positioned close to the ground plane for efficient RF coupling while preventing direct arcing paths. The insulator thus enables both close spacing for efficiency and arcing prevention for reliability.
2Temperature
If the dielectric layer thickness is reduced to improve cooling efficiency, then temperature uniformity improves, but shunt capacitances increase
Solution Approach 1:
The patent segments the electrical functions by using separate RF and DC electrodes, which allows the dielectric layer to be optimized for thermal management without compromising electrical performance. The separated electrode structure reduces the impact of shunt capacitance by providing dedicated RF coupling paths that are less sensitive to dielectric thickness variations, enabling thinner dielectrics for better temperature uniformity.
Solution Approach 2:
The patent changes the electrical configuration parameters by introducing distinct RF and DC electrodes with different functional requirements. This parameter change allows the system to operate with reduced dielectric thickness, as the separated electrodes create more favorable electrical field distributions that reduce shunt capacitance effects compared to a single embedded electrode configuration.
3Force
If a DC biased, RF floating electrode is used for electrostatic clamping, then electrostatic clamping effectiveness improves, but difficulty in delivering both RF power and DC voltage increases
Solution Approach 1:
The patent segments the power delivery system into separate DC and RF pathways with dedicated electrodes for each function. The DC electrode delivers voltage for electrostatic clamping, while the RF electrode delivers radio frequency power independently. This segmentation resolves the complexity of delivering both power types through a single electrode by providing separate, optimized delivery paths for each electrical function.
Solution Approach 2:
The insulator element serves multiple functions simultaneously: it provides electrical insulation between the RF electrode and ground plane, enables close spacing for RF efficiency, and allows the RF electrode to float at RF potentials while maintaining DC isolation. This multi-functionality reduces overall system complexity despite the separated electrode structure.
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 reduces the likelihood of arcing and allows for efficient, compact power delivery to the chuck, ensuring effective electrostatic clamping and temperature control during plasma processing.
Implementation Method 1
a center conductor to be coupled to the chuck electrode
Implementation Method 2
an annular RF transmission line to be coupled to the RF powered electrode
Implementation Method 3
An insulator is disposed between the center conductor and the RF transmission line
Implementation Method 4
a DC biased, but RF floating chuck electrode for electrostatically holding a workpiece to the chuck
Data Source
AI summary
A triaxial rod assembly for providing both RF power and DC voltage to a chuck assembly that supports a workpiece in a processing chamber during a manufacturing operation. In embodiments, a rod assembly includes a center conductor to be coupled to a chuck electrode for providing DC voltage to clamp a workpiece. Concentrically surrounding the center conductor is an annular RF transmission line to be coupled to an RF powered base to provide RF power to the chuck assembly. An insulator is disposed between the center conductor and RF transmission line. Concentrically surrounding the RF transmission line is a ground plane conductor coupled to a grounded base of the chuck to provide a reference voltage relative to the DC voltage. An insulator is disposed between the RF transmission line and the ground plane conductor.