Edge Ring Potential Control for Plasma Etch Uniformity
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Solution Overview
Problem
Current substrate manufacturing technologies face challenges in maintaining uniformity and process results across larger substrates due to edge effects, such as electric field disruptions and non-uniform ion angular distribution, leading to non-uniform etch profiles and polymer deposition issues that affect device yield.
Innovation Solution
The method involves controlling the DC voltage of an edge ring relative to the substrate in a plasma processing chamber, optimizing the ion directionality by adjusting the edge ring potential to be greater than, equal to, or less than the substrate potential, using a configurable DC power source and RF filter to manage harmonic energy, ensuring uniform or non-uniform ion angular distribution as needed for specific etch applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing is used on large substrates, then substrate throughput is maintained, but process uniformity deteriorates due to edge effects
Solution Approach 1:
The patent applies different electrical potentials to different regions of the substrate support structure. Specifically, the edge ring is biased relative to the center region, creating locally optimized electric fields that compensate for edge effects. This local quality adjustment ensures uniform ion angular distribution across the entire substrate surface, resolving the uniformity issue for large substrates.
Solution Approach 2:
The patent dynamically adjusts the electrical potential parameters of the edge ring and center region to optimize the plasma sheath configuration. By changing the bias voltage applied to the edge ring relative to the substrate, the system controls ion directionality and maintains consistent etch profiles across the substrate, effectively addressing the uniformity challenge.
2Manufacturing precision
If edge ring is electrically connected to chuck, then structural support is simplified, but ion angular distribution uniformity deteriorates
Solution Approach 1:
The patent electrically isolates the edge ring from the chuck by introducing an insulating layer, thereby segmenting the electrical structure. This segmentation allows independent electrical control of the edge ring potential, enabling optimization of ion angular distribution without being constrained by a direct electrical connection to the chuck.
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the edge ring and the chuck. This intermediary component provides electrical isolation while maintaining mechanical support, allowing the edge ring to be independently biased to control ion directionality and achieve uniform angular distribution.
3Productivity
If polymer byproducts accumulate on substrate edge, then process chemistry is maintained, but device yield deteriorates due to peeling and contamination
Solution Approach 1:
The patent modifies the electrical potential parameters at the substrate edge by biasing the edge ring, which alters the ion energy and angular distribution in the plasma sheath. This parameter change suppresses excessive polymer deposition on the substrate edge and prevents polymer peeling, thereby improving device yield.
Solution Approach 2:
The patent creates a composite structure at the substrate edge involving the edge ring, insulating layer, and substrate. This composite configuration enables controlled electrical fields that manage polymer formation and adhesion, preventing harmful polymer effects while maintaining necessary process chemistry.
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 approach allows for precise control of ion directionality and polymer removal, enhancing etch uniformity and yield by optimizing the plasma sheath and reducing polymer deposition on the substrate edge, thereby improving the manufacturing process and reducing defects.
Implementation Method 1
the edge ring having an edge ring potential relative to the DC potential of the substrate... control the ion directionality at the substrate edge
Implementation Method 2
generating a plasma within the plasma processing chamber to process the substrate
Implementation Method 3
a source RF generated by source RF generator 110 is commonly used to generate the plasma as well as control the plasma density via capacitively coupling
Data Source
AI summary
A method for processing a substrate in a plasma processing chamber. The substrate is disposed above a chuck and surrounded by an edge ring while the edge ring being electrically isolated from the chuck. The method includes providing RF power to the chuck and providing a edge ring DC voltage control arrangement. The edge ring DC voltage control arrangement is coupled to the edge ring to provide first voltage to the edge ring, with the edge ring potential being one of a positive potential, a negative potential and a ground. The method further includes generating a plasma within the plasma processing chamber to process the substrate. The substrate is processed while the edge ring DC voltage control arrangement is configured to cause the edge ring potential to be less than a DC potential of the substrate in an embodiment and to be substantially equal to the DC potential of the substrate in another embodiment.