Anti-Arc Zero Field Plate for PECVD Chamber Plasma Control
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Solution Overview
Problem
As substrate sizes increase in plasma enhanced chemical vapor deposition (PECVD) chambers, the likelihood of arcing and parasitic plasma formation increases, leading to inefficiencies and higher costs due to the increased RF current required for larger backing plates.
Innovation Solution
The implementation of an electrically conductive bracket spaced apart from the showerhead and an electrical isolator, which includes a plate, a lower portion, an upper portion, and a vertical extension, to minimize potential arcing and parasitic plasma by eliminating spaces where electric potential can exist, using materials like polytetrafluoroethylene for insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the backing plate size is increased to process large area substrates, then the processing capability is improved, but the RF current requirement increases leading to arcing and parasitic plasma formation
Solution Approach 1:
An electrically conductive bracket is introduced as an intermediary component between the showerhead and the chamber body. The bracket is positioned to eliminate spaces where electric potential can exist, thereby preventing arcing and parasitic plasma formation while allowing the large backing plate to function properly
Solution Approach 2:
The electrically conductive bracket creates an equipotential path that eliminates electric potential differences in spaces where arcing could occur. By maintaining equal potential across critical interfaces, the bracket prevents the formation of parasitic plasma while preserving the large backing plate area needed for processing large substrates
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 occurrence of arcing and parasitic plasma, enhancing the efficiency and cost-effectiveness of substrate processing by maintaining uniform plasma generation and reducing the risk of RF power usurpation.
Implementation Method 1
An electrical isolator having a first side contacting the plate of the electrically conductive bracket and a second side contacting the chamber body
Data Source
AI summary
Embodiments of the present invention generally relate to apparatus for reducing arcing and parasitic plasma in substrate processing chambers. The apparatus generally include a processing chamber having a substrate support, a backing plate, and a showerhead disposed therein. A showerhead suspension electrically couples the backing plate to the showerhead. An electrically conductive bracket is coupled to the backing plate and spaced apart from the showerhead. The electrically conductive bracket may include a plate, a lower portion, an upper portion, and a vertical extension. The electrically conductive bracket contacts an electrical isolator.