Confined PECVD Chamber Plasma Uniformity
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Solution Overview
Problem
As semiconductor device geometries shrink and fabrication processes become more complex, there is a growing need for uniform processing conditions to maintain tolerance against non-uniformity in semiconductor manufacturing, which current technologies struggle to achieve effectively.
Innovation Solution
The apparatus and method involve a processing chamber with a conductive gas distributor coupled to RF power, a powered electrode insulated from the gas distributor, and a shield member to create a uniform plasma processing environment, including a substrate support and a lid assembly with a gas distributor and tuning electrode to ensure uniform electric and thermal fields, reducing non-uniformity and chemical attack on chamber components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional PECVD chambers are used with large substrate areas, then processing capacity increases, but plasma uniformity deteriorates
Solution Approach 1:
The chamber is divided into distinct zones: a processing zone containing the substrate and plasma generation region, and a separate pump plenum region for exhaust. This segmentation allows independent optimization of plasma uniformity in the processing zone while maintaining efficient pumping capacity through the dedicated plenum volume, resolving the contradiction between large processing area and plasma uniformity.
2Volume of stationary object
If chamber volume is increased to accommodate larger substrates, then processing capacity improves, but thermal control uniformity worsens
Solution Approach 1:
The lid assembly incorporates localized heating zones with independent temperature control for different regions of the substrate support. This allows each local area to be optimized for its specific thermal requirements, maintaining uniform thermal conditions across the entire large substrate area despite the increased chamber volume.
3Productivity
If processing chamber size is enlarged for future substrate formats, then manufacturing capacity increases, but chemical attack on chamber components worsens
Solution Approach 1:
The pump plenum acts as an intermediary chamber volume that separates the plasma processing region from the exhaust pumping system. This intermediate zone captures and contains reactive plasma byproducts and chemical species before they can reach and attack the chamber walls and pumping components, thereby protecting the chamber structure while maintaining large processing capacity.
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 solution enhances uniformity in plasma processing, reducing thermal and chemical disturbances, and improves plasma density uniformity, leading to more consistent semiconductor substrate processing and extended equipment lifespan.
Implementation Method 1
forming a plasma from the processing gas
Implementation Method 2
coulpling RF power to a conductive gas distributor
Implementation Method 3
shaping the plasma by applying an electric potential to the electrode
Implementation Method 4
reducing thermal and chemical disturbances
Implementation Method 5
flowing a processing gas through the gas distributor into a processing region
Data Source
AI summary
An apparatus for plasma processing a substrate is provided. The apparatus comprises a processing chamber, a substrate support disposed in the processing chamber, a shield member disposed in the processing chamber below the substrate support, and a lid assembly coupled to the processing chamber. The lid assembly comprises a conductive gas distributor coupled to a power source, and an electrode separated from the conductive gas distributor and the chamber body by electrical insulators. The electrode is also coupled to a source of electric power. The substrate support is formed with a stiffness that permits very little departure from parallelism. The shield member thermally shields a substrate transfer opening in the lower portion of the chamber body. A pumping plenum is located below the substrate support processing position, and is spaced apart therefrom.