Peripheral RF Feed Chuck Assembly Azimuthal Uniformity
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Solution Overview
Problem
Non-uniform etching in wafer processing for integrated circuits leads to yield reduction, especially as critical dimensions shrink and wafer sizes increase, necessitating stringent control of non-uniformity to enable advanced technology nodes in cost-effective mass production.
Innovation Solution
A chuck assembly with a peripheral RF feed and symmetric RF return system, where RF power is delivered via a hollow feed contacting the facility plate's periphery, bypassing central conducting components, and a grounded shield provides a symmetrical RF return path, ensuring high azimuthal uniformity and minimizing interference from components like heating and clamping devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If RF power is delivered through a central feed to the facility plate, then the RF power can be effectively transmitted, but the conducting components (heating devices, clamping devices, lift pins) within the central region interfere with the RF field distribution, causing azimuthal non-uniformity
Solution Approach 1:
The RF feed is segmented into a peripheral portion that contacts only the peripheral region of the facility plate, separating the RF power delivery path from the central conducting components. This segmentation prevents interference between RF fields and central components, achieving both effective power transmission and azimuthal uniformity
Solution Approach 2:
A dielectric material is introduced as an intermediary between the peripheral RF feed and the facility plate. This dielectric layer enables RF power transmission while electrically isolating the feed from direct contact with the conductive facility plate, reducing unwanted RF interactions and improving field distribution uniformity
2Adaptability or versatility
If conducting components (heating devices, clamping devices, lift pins) are placed in the central region of the facility plate, then the chuck assembly can perform thermal control and mechanical operations, but these components disrupt the symmetry of the RF field, increasing azimuthal non-uniformity
Solution Approach 1:
The RF feed is extracted from the central region and repositioned to the periphery of the facility plate. This extraction removes the source of RF interference from the central conducting components, allowing both the thermal/mechanical functions and azimuthal uniformity to coexist
Solution Approach 2:
The RF power delivery is moved from a two-dimensional central plane to a three-dimensional peripheral configuration. The hollow feed structure extends vertically and peripherally, delivering RF power from a different spatial dimension that avoids interference with central components while maintaining field symmetry
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 significantly reduces azimuthal non-uniformity, maintaining low levels across a range of RF power settings and improving etch rates and residual scans, enhancing the uniformity and efficiency of plasma processing.
Implementation Method 1
a peripheral RF feed configured to deliver RF power, the peripheral RF feed having a first portion contacting a periphery of the facility plate
Implementation Method 2
a symmetrical, grounded shield substantially surrounding the peripheral RF feed
Implementation Method 3
an electrostatic chuck having a substrate support surface on a first side
Data Source
AI summary
Systems and methods are presented for a peripheral RF feed and symmetric RF return for symmetric RF delivery. According to one embodiment, a chuck assembly for plasma processing is provided. The chuck assembly includes an electrostatic chuck having a substrate support surface on a first side, a facility plate coupled to the electrostatic chuck on a second side that is opposite the substrate support surface, a peripheral RF feed configured to deliver RF power, the peripheral RF feed having a first portion contacting a periphery of the facility plate and an RF strap coupling the peripheral RF feed to an RF source.