Guard Aperture for Ion Angular Distribution Control
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Solution Overview
Problem
Current plasma processing systems face challenges in controlling ion angular distribution, particularly for 3D doping applications where higher incident angles are required for better conformality, and in treating photoresist after implant and etch processes without impacting the underlying substrate.
Innovation Solution
The introduction of a guard aperture and a control aperture between the plasma sheath and the workpiece, along with a guard plate that isolates the electrical field of the control aperture from the plasma sheath, allows for precise control of ion angular distribution by modifying the electric field lines and ion trajectories, enabling a bimodal ion angular distribution for improved process control and conformal doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a control aperture is introduced to modify ion angular distribution, then ion angular distribution control is improved, but the electrical field of the control aperture interferes with the plasma sheath
Solution Approach 1:
A guard aperture is introduced as an intermediary component between the plasma sheath and the control aperture. The guard aperture acts as a mediator that prevents the electrical field generated by the control aperture from interfering with the plasma sheath, while still allowing the control aperture to effectively modify ion angular distribution. This intermediary structure resolves the conflict by isolating the harmful electrical field effect while preserving the useful ion control function.
Solution Approach 2:
The aperture system is segmented into two distinct components: a guard aperture and a control aperture. This segmentation separates the functions of plasma sheath protection (guard aperture) and ion angular distribution control (control aperture), allowing each component to perform its specific function without interfering with the other. The guard aperture segment handles electrical field isolation, while the control aperture segment handles ion trajectory modification.
2Manufacturing precision
If higher incident angles are used for 3D doping, then conformality is improved, but control over ion angular distribution becomes more difficult
Solution Approach 1:
The system enables dynamic control of ion angular distribution by adjusting the bias voltage applied to the workpiece holder. By varying the bias voltage, the ion angular distribution can be dynamically modified to achieve different incident angles, allowing optimization for both conformality in 3D structures and simplified control conditions. This dynamic adjustment capability resolves the contradiction by making the system adaptable to different processing requirements.
Solution Approach 2:
The invention utilizes parameter changes in the electrical field (through bias voltage adjustment) to control ion trajectories and incident angles. By changing the electrical field parameters, the system can achieve higher incident angles for improved conformality while maintaining control over the angular distribution. The parameter changes allow flexible optimization of the ion-plasma interaction for different processing scenarios.
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 enables better profile control and selectivity in plasma processes, allowing for uniform doping of three-dimensional structures and easier removal of photoresist, while maintaining precise control over ion energy distribution and angle, enhancing the effectiveness of plasma processing for various applications.
Implementation Method 1
a plasma source to generate a plasma containing gas ions in the plasma chamber, the plasma forming a sheath above the workpiece, the sheath having an electric field
Implementation Method 2
a workpiece holder in the chamber to apply a bias voltage to the workpiece to attract ions across the plasma sheath to be incident on the workpiece
Implementation Method 3
a control aperture between the sheath and the workpiece, the aperture being positioned to modify an angular distribution of the ions that are incident on the workpiece
Implementation Method 4
a guard aperture between the sheath and the control aperture to isolate an electrical field of the control aperture from the plasma sheath
Data Source
AI summary
A guard aperture is described to control the ion angular distribution in plasma processing in one example a workpiece processing system has a plasma chamber, a plasma source to generate a plasma containing gas ions in the plasma chamber, the plasma forming a sheath above the workpiece, the sheath having an electric field, a workpiece holder in the chamber to apply a bias voltage to the workpiece to attract ions across the plasma sheath to be incident on the workpiece, a control aperture between the sheath and the workpiece, the aperture being positioned to modify an angular distribution of the ions that are incident on the workpiece, and a guard aperture between the sheath and the control aperture to isolate an electrical field of the control aperture from the plasma sheath.