Adjustable Gap Plasma Chamber for Differential Pressure Control
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Solution Overview
Problem
Conventional plasma processing systems lack the capability for differential pressure control across different regions of the plasma processing chamber, limiting the range of pressure that can be achieved and affecting plasma density and uniformity, especially in multi-step semiconductor device manufacturing processes.
Innovation Solution
The system incorporates an upper electrode peripheral extension (UE-PE) that is non-coplanar with the upper electrode and a cover ring surrounding the lower electrode, allowing for adjustable gaps to create narrow and wide gap configurations, enabling ultra-high pressure and low conductance or low pressure and high conductance regimes, respectively, through active feedback loops and gas flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If confinement ring gaps are adjusted to control pressure in the plasma generating region, then pressure control is achieved, but the operating pressure range is limited and plasma cross section remains fixed
Solution Approach 1:
The chamber is divided into multiple regions with different gap configurations: a first gap between the upper electrode and lower electrode for plasma generation, and a second gap between the upper electrode peripheral extension and cover ring for plasma confinement. This segmentation allows independent control of plasma cross section and pressure range.
Solution Approach 2:
The invention adds a vertical dimension to pressure control by introducing the upper electrode peripheral extension that extends beyond the upper electrode edge. This creates a new gap dimension (second gap) that is independent from the primary plasma generation gap, enabling extended pressure control range without fixing plasma cross section.
2Device complexity
If a single gap configuration is used, then device simplicity is maintained, but differential pressure control in different chamber regions is not possible
Solution Approach 1:
The chamber structure is segmented into distinct gap regions: the first gap for plasma generation and the second gap for plasma confinement. This segmentation enables differential pressure control in different chamber regions while maintaining overall structural simplicity.
Solution Approach 2:
Different gap configurations are provided in different regions of the chamber: the first gap between electrodes for plasma generation and the second gap between the peripheral extension and cover ring for confinement. Each region has optimized local properties for its specific function.
3Ease of manufacture
If the upper electrode peripheral extension is made coplanar with the upper electrode, then manufacturing simplicity is maintained, but adjustable gap configuration for different pressure regimes is not possible
Solution Approach 1:
The upper electrode peripheral extension is positioned asymmetrically relative to the upper electrode, extending beyond its edge. This asymmetric configuration enables the creation of the second gap with independent dimensions, allowing flexible adjustment for different pressure regimes while maintaining straightforward manufacturing.
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 allows for a wide range of pressure control from 0.67 Pa to 667 Pa, enabling precise plasma processing conditions for various semiconductor recipes within the same chamber, reducing the need for multiple processing chambers and improving yield and efficiency.
Implementation Method 1
A typical processing system that may be employed to perform substrate processing may be a capacitively-coupled plasma (CCP) processing system
Implementation Method 2
The overall gas flow conductance out of the plasma generating region may depend on several factors, including but not limited to, the number of confinement rings and the size of the gaps between the confinement rings
Data Source
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AI summary
A plasma processing system having a plasma processing chamber configured for processing a substrate is provided. The plasma processing system includes at least an upper electrode and a lower electrode for processing the substrate. The substrate is disposed on the lower electrode during plasma processing, where the upper electrode and the substrate forms a first gap. The plasma processing system also includes an upper electrode peripheral extension (UE-PE). The UE-PE is mechanically coupled to a periphery of the upper electrode, where the UE-PE is configured to be non-coplanar with the upper electrode. The plasma processing system further includes a cover ring. The cover ring is configured to concentrically surround the lower electrode, where the UE-PE and the cover ring forms a second gap.