Plasma Edge Ring Coil for Ion Tilt Correction
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Solution Overview
Problem
The tilting of ions in the plasma sheath at the edge region of wafers during semiconductor fabrication leads to defects and reduced fabrication yield due to limitations in existing plasma processing systems.
Innovation Solution
A plasma processing system with an edge ring assembly that includes a dielectric ring with a coil embedded within, generating a magnetic field to adjust the direction of ions, thereby correcting the tilt and achieving uniformity in trench formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing systems are used, then the fabrication process can be performed, but ion tilting occurs at the wafer edge region leading to defective trenches and reduced fabrication yield
Solution Approach 1:
The patent applies local quality by implementing an edge ring assembly with coils specifically at the wafer edge region, where the problem of ion tilting occurs. The edge ring assembly is positioned only at the periphery of the wafer, applying localized magnetic fields to correct ion direction in the problematic edge area without affecting the central region. This targeted approach improves trench profile uniformity at the edge while maintaining overall fabrication yield.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary mechanism to mediate between the plasma ions and the wafer surface. The coils in the edge ring assembly generate magnetic fields that act as a mediator to redirect tilted ions, correcting their trajectory before they reach the wafer edge. This intermediary magnetic field resolves the ion tilting issue without requiring direct mechanical intervention.
2Productivity
If the number of dies per wafer is increased, then productivity improves, but the proportion of dies at the edge region increases leading to more defects
Solution Approach 1:
By applying local quality through the edge ring assembly, the patent enables high-density wafer processing while maintaining edge region quality. The localized correction at the wafer periphery allows more dies to be processed per wafer without sacrificing the quality of edge-region dies, thus resolving the contradiction between productivity and manufacturing precision.
3Reliability
If edge ring assembly with coils is added, then ion direction is corrected and fabrication yield improves, but device complexity increases
Solution Approach 1:
The patent reduces device complexity by applying the edge ring assembly only where needed - at the wafer edge region - rather than implementing a uniform correction system across the entire wafer. This localized approach improves fabrication yield while minimizing the added complexity compared to a full-wafer solution.
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 system effectively corrects the ion direction, reducing tilted trench profiles at the wafer edge and enhancing the fabrication yield by ensuring ions are perpendicular to the wafer surface, thus improving the semiconductor process.
Implementation Method 1
the coil generating a magnetic field to adjust the direction of ions
Implementation Method 2
supplying a voltage to the coil to generate a magnetic field, wherein the magnetic field generates a force applied to the ions in the plasma
Data Source
AI summary
A plasma processing system is provided. The plasma processing system includes an edge ring assembly that includes a dielectric ring and a coil. The coil is embedded within the dielectric ring. The coil generates a magnetic field that affects the ions in the proximity of the plasma sheath and in turn increases the fabrication yield of the semiconductor process.