Plasma Grid Assembly for Edge Uniformity in Semiconductor Processing
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Solution Overview
Problem
Current plasma processing techniques exhibit non-uniformity of plasma distribution near the edge of semiconductor substrates due to recombination of plasma on chamber walls.
Innovation Solution
A plasma processing apparatus with a grid assembly that includes a grid suspended above the substrate support, featuring holes and outer openings to control plasma flow, ensuring uniform distribution across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If plasma is processed using conventional direct plasma processing, then high density plasma and reactive species are produced for substrate processing, but non-uniformity of plasma distribution occurs near the edge of the substrate due to recombination on chamber walls
Solution Approach 1:
The grid is segmented into multiple regions with different opening characteristics: a first region with a first opening ratio and a second region with a second opening ratio. This segmentation allows different plasma flow rates to different areas of the substrate, specifically compensating for edge region losses and achieving uniform plasma distribution across the substrate surface.
Solution Approach 2:
Different regions of the grid are assigned different opening ratios to create local quality variations. The first region (typically corresponding to edge areas) has a higher opening ratio to compensate for recombination losses, while the second region (central area) has a lower opening ratio. This local differentiation ensures uniform plasma distribution across the entire substrate.
2Device complexity
If plasma flows directly to the substrate without a grid, then the structure is simple, but plasma recombines on chamber walls near the substrate edge causing non-uniform distribution
Solution Approach 1:
The grid is divided into multiple regions with different opening ratios to control plasma flow distribution. This segmentation addresses the uniformity problem while keeping the overall device structure relatively simple compared to more complex plasma generation systems.
Solution Approach 2:
The grid acts as an intermediary component between the plasma source and the substrate. It mediates plasma flow by providing different opening ratios in different regions, controlling how plasma reaches the substrate surface and compensating for edge recombination effects without requiring fundamental changes to the plasma source or chamber structure.
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 grid assembly enhances plasma uniformity by directing plasma to both the central and edge regions of the substrate, reducing recombination on chamber walls and improving overall plasma distribution.
Implementation Method 1
Plasma received from a plasma source is configured to flow through the plurality of holes and the one or more outer openings of the grid towards the substrate support
Data Source
AI summary
Embodiments of the present disclosure generally relate to high efficiency inductively coupled plasma sources and plasma processing apparatus. Specifically, embodiments relate to grids to improve plasma uniformity. In one embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a processing chamber, a substrate support disposed within the processing chamber, a grid support coupled to the processing chamber, and a grid. The grid is coupled to the grid support and disposed above the substrate support. The grid has a plurality of holes and one or more outer openings defined between a circumference of the grid and the grid support. Plasma received from a plasma source is configured to flow through the plurality of holes and the one or more outer openings of the grid towards the substrate support.