Spin Dry Etching for Uniform Plasma and CD Control
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Solution Overview
Problem
Conventional dry etching systems suffer from plasma distribution uniformity issues, leading to degraded lateral edge roughness (LER) and critical dimension (CD) uniformity, especially as semiconductor device feature sizes shrink, due to the fixed placement of the exhaust pumping port and etching gas injection locations.
Innovation Solution
A spin dry etching system where the object to be etched is rotated during the process, improving plasma distribution uniformity and allowing for controlled lateral etching profiles by adjusting spin speed, and a holder apparatus with a laterally-protruding clamp to secure the object and prevent movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the exhaust pumping port and etching gas injection locations are fixed in conventional dry etching systems, then the system structure is simple and easy to manufacture, but plasma distribution uniformity deteriorates leading to degraded lateral edge roughness and critical dimension uniformity
Solution Approach 1:
The patent applies the dynamics principle by rotating the substrate holder during the dry etching process. This dynamic motion transforms the static plasma distribution problem into a dynamic one where the substrate continuously moves through different plasma density regions, achieving uniform etching across the substrate surface despite fixed gas injection and exhaust port locations. The rotation speed is controlled to optimize plasma distribution uniformity while maintaining manufacturing precision.
2Manufacturing precision
If the object to be etched is rotated during the dry etching process, then plasma distribution uniformity is improved, but the device complexity increases due to additional rotation mechanisms
Solution Approach 1:
The patent applies the universality principle by designing the holder apparatus to serve multiple functions: it not only holds the substrate but also provides the rotation mechanism, clamping, and positioning all in one integrated structure. The laterally-protruding clamp design achieves both secure substrate fixation and enables rotation, reducing the need for separate components and minimizing overall device complexity while improving lateral edge roughness through controlled rotation.
3Manufacturing precision
If the spin speed is increased to improve plasma distribution uniformity, then lateral edge roughness improves, but the lateral etching profile becomes harder to control
Solution Approach 1:
The patent applies the feedback principle by implementing a controlled rotation system where the spin speed is regulated based on real-time monitoring of etching progress and plasma distribution. The laterally-protruding clamp design provides mechanical feedback to maintain consistent substrate positioning during rotation. This feedback mechanism allows the system to achieve improved critical dimension uniformity through optimized spin speeds while maintaining ease of operation by automatically adjusting parameters to preserve lateral etching profile control.
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 spinning of the object enhances plasma distribution uniformity, reducing LER and CD variations, and enables controllable lateral etching profiles, improving semiconductor device performance and fabrication accuracy.
Implementation Method 1
The object is spun while the dry etching process is being performed
Data Source
AI summary
A spin dry etching process includes loading an object into a dry etching system. A dry etching process is performed to the object, and the object is spun while the dry etching process is being performed. The spin dry etching process is performed using a semiconductor fabrication system. The semiconductor fabrication system includes a dry etching chamber in which a dry etching process is performed. A holder apparatus has a horizontally-facing slot that is configured for horizontal insertion of an etchable object therein. The etchable object includes either a photomask or a wafer. A controller is communicatively coupled to the holder apparatus and configured to spin the holder apparatus in a clockwise or counterclockwise direction while the dry etching process is being performed. An insertion of the etchable object into the horizontally-facing slot of the holder apparatus restricts a movement of the object as the dry etching process is performed.