Electrostatic Chuck Faraday Cage for Uniform RF Delivery
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Solution Overview
Problem
Existing semiconductor chip fabrication processes face challenges in uniformly transmitting radiofrequency (RF) signals through electrostatic chucks due to variations in internal structures, leading to azimuthal non-uniformity and potential damage from parasitic plasma formation.
Innovation Solution
An electrostatic chuck design featuring a ceramic layer with a primary RF power delivery electrode positioned below a clamp electrode and surrounded by RF power delivery connection modules, forming a Faraday cage to direct RF power transmission uniformly and avoid internal interference, ensuring consistent RF signal delivery across a broad frequency spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If RF signals are transmitted through the internal structure of the electrostatic chuck, then RF power can be delivered to the plasma processing region, but azimuthal non-uniformity occurs due to variations in internal structure
Solution Approach 1:
The electrostatic chuck is segmented into distinct functional layers: a base plate for RF signal input, a ceramic layer for insulation and support, and embedded Faraday cage structures for controlled RF distribution. This segmentation allows RF power to be delivered uniformly by distributing it through multiple discrete connection modules around the perimeter rather than relying on uniformity through the entire internal structure.
Solution Approach 2:
The Faraday cage acts as an intermediary structure between the RF power delivery electrode and the plasma processing region. It controls and directs RF power transmission through designated paths, preventing direct coupling that would cause azimuthal non-uniformity. The Faraday cage shields the internal volume while allowing controlled RF delivery through the ceramic layer to the substrate.
2Adaptability or versatility
If RF signals are transmitted through the electrostatic chuck, then plasma can be generated and biased, but parasitic plasma formation occurs causing potential damage
Solution Approach 1:
The Faraday cage, which initially serves to block RF signals from reaching internal components, is strategically configured to convert this shielding effect into a beneficial feature. By containing RF fields within designated transmission paths and preventing them from coupling with internal structures, the Faraday cage eliminates parasitic plasma formation while still allowing effective RF power delivery to the plasma processing region through the ceramic layer and substrate.
3Ease of manufacture
If the internal structure of the electrostatic chuck varies, then different electrostatic chucks can be manufactured, but variation in RF signal transmission occurs
Solution Approach 1:
The Faraday cage structure serves multiple functions simultaneously: it provides electrical shielding to prevent parasitic plasma, acts as an RF signal distribution network through the base plate and connection modules, and maintains mechanical support for the ceramic layer. This multi-functionality ensures that despite variations in manufacturing, the RF signal transmission remains consistent because the Faraday cage configuration standardizes the RF delivery path across all electrostatic chucks.
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 design enhances RF signal consistency and safety, reducing the risk of parasitic plasma formation and damage to internal components, while maintaining uniformity in RF current transmission to the plasma processing region, independent of internal circuitry variations.
Implementation Method 1
The base plate, the plurality of RF power delivery connection modules, and the primary RF power delivery electrode together form a Faraday cage to direct RF power transmission around an internal volume of the electrostatic chuck
Implementation Method 2
electrostatic chuck is disclosed. The electrostatic chuck includes a base plate formed of an electrically conductive material
Data Source
AI summary
A ceramic layer is attached to a top surface of a base plate using a bond layer. The ceramic layer has a top surface configured to support a substrate. At least one clamp electrode is positioned within an upper region of the ceramic layer. A primary radiofrequency (RF) power delivery electrode is positioned within the ceramic layer at a location vertically below the at least one clamp electrode such that a region of the ceramic layer between the primary RF power delivery electrode and the at least one clamp electrode is substantially free of other electrically conductive material. A plurality of RF power delivery connection modules is distributed in a substantially uniform manner about a perimeter of the ceramic layer. Each of the RF power delivery connection modules is configured to form an electrical connection from the base plate to the primary RF power delivery electrode at its respective location.