Plasma Etch Angle Compensation for Shifted Wafer Overlayers
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Solution Overview
Problem
In plasma etching processes, especially for high aspect ratio features, achieving precise control over ion approach angles is challenging due to misalignment and metrology errors, which can lead to incomplete exposure and feature misformation during semiconductor fabrication.
Innovation Solution
A plasma etching system with a local adjustment blocker and a controller that adjusts the ion approach angle based on metrology measurements, allowing for precise control over the direction of plasma particles hitting the wafer surface, compensating for misalignment and ensuring complete exposure of features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma etching is used for high aspect ratio features, then etching capability is improved, but control over ion approach angles deteriorates due to misalignment and metrology errors
Solution Approach 1:
The patent applies local quality by making the ion approach angle adjustable for different regions of the wafer. The controller enables independent angle adjustment for each radial position, allowing precise control of ion bombardment direction in areas with misalignment while maintaining standard etching elsewhere. This resolves the contradiction by providing localized precision without sacrificing overall etching productivity.
Solution Approach 2:
The patent implements dynamics by making the ion approach angle dynamically adjustable during the etching process. The controller can modify the angle in real-time based on detected misalignment, transforming a static etching process into a dynamic one that adapts to manufacturing variations. This enables precise angle control while maintaining high etching capability through continuous process optimization.
2Device complexity
If fixed ion approach angle is used, then process simplicity is maintained, but compensation for metrology errors is lost
Solution Approach 1:
The patent applies feedback by implementing a closed-loop control system where metrology measurements of actual feature positions are fed back to the controller. The controller then adjusts the ion approach angle based on detected deviations, creating a self-correcting process. This resolves the contradiction by adding intelligent control that improves reliability while maintaining operational simplicity through automated compensation.
Solution Approach 2:
The patent implements parameter changes by dynamically modifying the ion approach angle parameter based on process conditions and metrology data. Instead of using a fixed angle, the system adjusts this critical parameter in response to detected variations, enabling compensation for metrology errors while keeping the overall process simple through automated parameter optimization.
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 accurate and efficient plasma etching by compensating for metrology errors and misalignment, ensuring complete exposure and precise feature formation, thereby improving the quality and reliability of semiconductor fabrication.
Implementation Method 1
A plasma source is provided and configured to emit plasma of ions into a plasma processing chamber and toward a wafer stage
Implementation Method 2
RIE or ion-enhanced etching works by a combination of physical bombardment by ions, chemical etching by radicals and ions
Implementation Method 3
The plasma source, known as etch species, can be either charged (ions) or neutral (atoms and radicals)
Implementation Method 4
the plasma generates volatile etch products at room temperature from the chemical reactions between the elements of the material etched and the reactive species generated by the plasma
Data Source
AI summary
The current disclosure includes a plasma etching system that includes a movable plasma source and a moveable wafer stage. A relative position between the movable plasma source and the movable wafer stage can be varied to set up an angle along which plasma particles of the plasma hits a wafer positioned on the wafer stage.