Edge Ring Assembly with Dielectric Spacer for Plasma Etching
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Solution Overview
Problem
During plasma etching in semiconductor processing, the photoresist layer is often removed along with the intended layers, leading to undesirable polymer buildup on the substrate's underside and edges, which affects process yield and uniformity.
Innovation Solution
An edge ring assembly is introduced, comprising a dielectric spacer ring and an edge ring, which creates clearance gaps to reduce RF coupling, arcing, and polymer deposition, while maintaining plasma uniformity and focusing RF power effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is performed to remove photoresist layer, then etching effectiveness is improved, but polymer buildup on substrate edges and underside increases
Solution Approach 1:
A dielectric spacer ring is introduced as an intermediary component between the conductive edge ring and the substrate support surface. This spacer ring acts as a mediator that prevents direct RF coupling and arcing, thereby reducing polymer deposition on the substrate edges and underside while maintaining the protective function of the edge ring assembly during plasma etching
2Reliability
If edge ring is placed close to substrate support surface, then plasma confinement is improved, but RF coupling and arcing increase
Solution Approach 1:
The dielectric spacer ring serves as an intermediary that decouples the RF fields between the conductive edge ring and the substrate support surface. By positioning this dielectric material between the two conductive surfaces, the system maintains close spacing for plasma confinement while preventing harmful RF coupling and arcing through the electrical insulation properties of the dielectric spacer
Solution Approach 2:
The edge ring assembly employs local quality differentiation by using a conductive edge ring for plasma confinement at the outer perimeter, while introducing a non-conductive dielectric spacer ring at the interface with the substrate support surface. This localized material differentiation allows the system to simultaneously achieve plasma confinement where needed while preventing RF coupling at the critical interface region
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 edge ring assembly significantly reduces polymer deposition on the substrate's underside and edges, enhancing plasma etching uniformity and process yield by minimizing RF coupling and arcing, and allowing for easier replacement of consumable parts.
Implementation Method 1
a dielectric spacer ring between the edge ring and the substrate support surface
Implementation Method 2
plasma is formed above the surface of a substrate by adding large amounts of energy to a gas (or gas mixture) at low pressure. The plasma may contain ions, free radicals, and neutral species with high kinetic energies
Implementation Method 3
Plasma etching can be made more effective by using gases that are chemically reactive with the material to be etched. So called 'reactive ion etching' combines the energetic etching effects of the plasma with the chemical etching effects of a reactive gas
Data Source
AI summary
An edge ring assembly surrounds a substrate support surface in a plasma etching chamber. The edge ring assembly comprises an edge ring and a dielectric spacer ring. The dielectric spacer ring, which surrounds the substrate support surface and which is surrounded by the edge ring in the radial direction, is configured to insulate the edge ring from the baseplate. Incorporation of the edge ring assembly around the substrate support surface can decrease the buildup of polymer at the underside and along the edge of a substrate and increase plasma etching uniformity of the substrate.