RF Return Path Electrode for PVD Substrate Support Uniformity
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Solution Overview
Problem
Physical vapor deposition (PVD) processes using radio frequency (RF) energy often experience non-uniformity issues due to conventional electrostatic chucks, leading to uneven film deposition.
Innovation Solution
The introduction of substrate supports with a radio frequency (RF) return path, including a dielectric support body with a chucking electrode and an RF return path electrode, provides a shorter and more efficient RF return path, reducing stray losses and improving process uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrostatic chucks are used in PVD chambers with RF energy, then substrate processing can be performed, but process non-uniformity and non-uniform film deposition occur
Solution Approach 1:
The patent extracts the RF return path function from the conventional electrostatic chuck design by adding a separate RF return path electrode. This dedicated return path electrode is disposed within the dielectric support body to provide a controlled RF current return path, separating the chucking function from the RF return path function and eliminating the stray losses that cause non-uniformity.
Solution Approach 2:
The RF return path electrode acts as an intermediary element between the chucking electrode and ground. It provides a controlled intermediate path for RF currents to return to ground, preventing direct coupling between RF power and ground that would cause non-uniformity. The dielectric support body serves as another intermediary, isolating the RF return path from the substrate support surface.
2Reliability
If conventional substrate supports are used, then substrate holding is achieved, but signal cross-talk and uncontrolled RF losses increase
Solution Approach 1:
The substrate support is segmented into distinct functional zones: a chucking electrode for substrate holding, an RF return path electrode for controlled RF current return, and a dielectric support body that electrically isolates these functions. This segmentation prevents signal cross-talk by separating the high-voltage chucking signals from the RF processing signals, while the dielectric material provides electrical isolation between different potential regions.
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 enhances processing uniformity by minimizing uncontrolled RF losses and signal cross-talk, resulting in more consistent substrate processing results.
Implementation Method 1
a chucking electrode disposed within the support body proximate the support surface
Implementation Method 2
an RF return path electrode disposed on the second surface of the dielectric support body
Data Source
AI summary
Embodiments of substrate supports having a radio frequency (RF) return path are provided herein. In some embodiments, a substrate support may include a dielectric support body having a support surface to support a substrate thereon and an opposing second surface; a chucking electrode disposed within the support body proximate the support surface; and an RF return path electrode disposed on the second surface of the dielectric support body. In some embodiments, a substrate processing system may include a process chamber having an inner volume; a shield to separate the inner volume into a processing volume and a non-processing volume and extending toward a ceiling of the process chamber; and a substrate support disposed below the shield, wherein the substrate support is as described above.