Annular Plasma Shield Structure for Parasitic Plasma Suppression
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Solution Overview
Problem
The generation of parasitic plasma in areas outside the intended region during plasma-enhanced processes in semiconductor processing systems leads to reduced energy efficiency, particle contamination, spatial and temporal nonuniformity, thermal shock, premature failure of chamber components, and electrical arcing, which increases manufacturing time and costs.
Innovation Solution
An annular shield structure with openings configured to suppress parasitic plasma generation, comprising a unitary body or spaced annular shield rings, supported by an annular support structure, and featuring bayonet-type engagement for secure attachment, allowing gas flow while minimizing plasma formation in unwanted areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power is supplied to generate plasma in the processing chamber, then deposition and etching rates are improved, but parasitic plasma is generated in unwanted areas
Solution Approach 1:
An annular shield structure is introduced as an intermediary component between the plasma source and the chamber walls. This shield structure with specifically designed openings blocks parasitic plasma generation in unwanted areas while allowing beneficial plasma to reach the substrate, thereby resolving the contradiction between maintaining high deposition/etching rates and preventing parasitic plasma
Solution Approach 2:
The shield structure implements local quality control by creating regions with different plasma permeability. The openings in the shield are strategically positioned and sized to allow plasma flow to the substrate while blocking plasma formation on chamber walls, thus locally suppressing parasitic plasma without affecting overall process productivity
2Power
If plasma is generated in unwanted areas, then energy is consumed, but this reduces energy efficiency
Solution Approach 1:
The shield structure converts the harmful effect of parasitic plasma into a beneficial outcome by using the plasma itself as a diagnostic tool. The presence of parasitic plasma indicates where the shield needs to be positioned, and the shield's design is optimized to allow beneficial plasma while blocking harmful plasma, thus improving energy efficiency
3Loss of energy
If parasitic plasma is suppressed using a shield structure, then energy efficiency is improved, but the device complexity increases
Solution Approach 1:
The shield structure is segmented into multiple components: an annular shield body with openings, support structures, and positioning mechanisms. This segmentation allows for modular assembly, easier adjustment of opening positions and sizes, and simplified maintenance, thereby reducing the practical complexity despite adding functional components
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 annular shield structure enhances energy efficiency by directing more power to the intended process area, reducing parasitic plasma-related issues, thereby increasing deposition and etching rates and preventing contamination, nonuniformity, and component failure.
Implementation Method 1
The openings respectively include a maximum dimension in a plane perpendicular to the axial direction that is less than or equal to about twice a plasma sheath thickness associated with the plasma-enhanced process
Data Source
AI summary
A parasitic plasma suppressor configured to suppress (or at least reduce) the generation of parasitic plasma outside an intended region, such as suppress the generation of parasitic plasma in areas adjacent a pedestal in a processing chamber of a plasma-enhanced processing system.