Multi-Electrode Electrostatic Chuck for RF Bias Arcing Control
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Solution Overview
Problem
RF power applied to the cooling plate in electrostatic chucks creates a DC potential difference between the substrate and the cooling plate, leading to arcing in the gas channels during substrate processing.
Innovation Solution
The electrostatic chuck design includes multiple electrodes embedded in the dielectric plate, with conductive elements coupling them to reduce the potential difference between the cooling plate and the substrate, thereby minimizing arcing in the gas channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If RF power is applied to the cooling plate to induce bias voltage on the substrate, then substrate processing capability is improved, but arcing occurs in the gas channels due to DC potential difference
Solution Approach 1:
The patent divides the single electrode structure into multiple electrodes (first electrode, second electrode, third electrode) distributed across the dielectric plate. This segmentation allows different regions to have different electrical potentials, reducing the overall potential difference between the cooling plate and substrate, thereby minimizing arcing in the gas channels while maintaining effective bias voltage for substrate processing
Solution Approach 2:
The patent creates equipotential regions by connecting multiple electrodes through conductive elements (posts). The first and second electrodes are electrically coupled to the cooling plate, while the third electrode is coupled to ground or a different potential. This equipotential arrangement reduces the DC potential difference across the gas channels, preventing arcing while maintaining the necessary bias voltage for ion attraction
2Reliability
If multiple electrodes and conductive elements are added to reduce potential difference, then arcing is minimized, but device complexity increases
Solution Approach 1:
The patent merges multiple electrodes into a single integrated electrostatic chuck assembly. The first, second, and third electrodes are embedded in the same dielectric plate and work together as a unified system. The conductive elements (posts) serve dual purposes: electrical connection and structural support. This merging approach reduces the number of separate components needed while achieving the goal of minimizing arcing
Solution Approach 2:
The conductive elements (posts) serve multiple functions: they electrically couple the electrodes to the cooling plate and ground, provide structural support for the electrode assembly, and maintain precise spacing between electrodes. This multi-functionality reduces the need for additional components, simplifying the overall device while maintaining reliability
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 multi-electrode configuration effectively reduces the peak-to-peak voltage difference between the cooling plate and the substrate, minimizing arcing and enhancing the reliability of substrate processing.
Implementation Method 1
An electrostatic chuck is used to electrostatically hold a substrate to control substrate temperature during processing
Implementation Method 2
a cooling plate disposed below the dielectric plate
Implementation Method 3
A backside gas may be introduced between the substrate and a top surface of the electrostatic chuck via gas channels in the electrostatic chuck as a heat transfer medium
Data Source
AI summary
Embodiments of an electrostatic chuck are provided herein. In some embodiments, an electrostatic chuck for use in a substrate processing chamber includes a plate having a first side and a second side opposite the first side, a first electrode embedded in the plate proximate the first side, a second electrode embedded in the plate proximate the second side, a plurality of conductive elements coupling the first electrode to the second electrode, a first gas channel disposed within the plate and between the first electrode and the second electrode, a gas inlet extending from the second side of the plate to the first gas channel; and a plurality of gas outlets extending from the first side of the plate to the first gas channel.