Ion Angle Detector With High Aspect Ratio Grid
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Solution Overview
Problem
Plasma processing technologies face challenges in precisely measuring ion energy and ion angle distribution functions, which are critical for fabricating high aspect ratio structures in semiconductor manufacturing, due to the sensitivity of processes like high aspect ratio contact etch and plasma-enhanced atomic layer etch to ion kinetic energy and direction.
Innovation Solution
A measurement system comprising a detector with an ion angle selection grid and ion current collectors, where the grid has high aspect ratio openings to selectively sample ions based on angle and energy, allowing for the computation of a two-dimensional joint ion distribution function, using techniques such as energy selection and physical rotation or multiple angle selectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detectors with low aspect ratio openings are used, then the device complexity is low and ease of manufacture is high, but the measurement precision of ion angle distribution is insufficient
Solution Approach 1:
The detector is segmented into multiple independent components: an ion angle selection grid with high aspect ratio openings, an ion energy selection grid, and an ion current collector. This segmentation allows each component to perform a specific function (angle selection, energy selection, current measurement) and enables precise measurement of ion angle distribution while maintaining manageable device complexity through modular design
Solution Approach 2:
The invention transitions from conventional low aspect ratio openings to high aspect ratio openings (depth/width ratio ≥ 40) in the ion angle selection grid. This dimensional change in the opening geometry creates a strong angular filter that selectively transmits ions based on their arrival angle, thereby significantly improving measurement precision without requiring overly complex device architecture
2Measurement precision
If high aspect ratio openings with depth to width ratio ≥ 40 are used in the ion angle selection grid, then the measurement precision of ion angle is improved, but the manufacturing difficulty increases
Solution Approach 1:
The ion angle selection grid is designed as a separate, standalone component with high aspect ratio openings, independent from other detector elements. This segmentation allows specialized fabrication techniques to be applied specifically to the grid structure, isolating the manufacturing complexity to a single component that can be optimized independently
Solution Approach 2:
The invention specifies a quantitative parameter threshold (depth/width ratio ≥ 40) for the high aspect ratio openings. This parameter definition provides clear fabrication targets and enables the use of specialized manufacturing techniques such as deep reactive ion etching (DRIE) or other high aspect ratio drilling methods, making the manufacturing process more controllable and repeatable despite the increased difficulty
3Adaptability or versatility
If multiple ion current collectors with different opening dimensions are used, then the adaptability for measuring different ion angle ranges is improved, but the device complexity increases
Solution Approach 1:
The detector employs multiple ion current collectors, each associated with specific openings of particular dimensions in the ion angle selection grid. This segmentation allows each collector-opening pair to be optimized for a specific ion angle range, providing adaptability while keeping the overall structure organized and manageable through systematic division of measurement functions
Solution Approach 2:
The ion angle selection grid serves multiple functions simultaneously: it acts as an angular filter for different ion angle ranges, provides structural support for multiple openings, and enables selective ion transmission to different current collectors. This multi-functionality reduces the need for separate components for each measurement function, thereby managing device complexity while enhancing adaptability
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
Enables precise measurement of ion angle and energy distribution, improving the precision and control of plasma processes, thereby enhancing the fabrication of complex 3D semiconductor structures with high aspect ratios.
Implementation Method 1
The detector includes an ion angle selection grid with a plurality of through openings extending through the ion angle selection substrate, where each of the plurality of through openings has a depth into the ion angle selection substrate and a width orthogonal to the depth, where a ratio of the depth to the width is greater than or equal to 40
Implementation Method 2
an ion current collector disposed within the cavity at an opposite side of the cavity below the ion angle selection grid
Data Source
AI summary
A measurement system for a plasma processing system includes a detector and an ion current meter coupled to the ion current collector and configured to provide a signal based on the measurements from the ion current collector. The detector includes an insulating substrate including a cavity, an ion angle selection grid configured to be exposed to a bulk plasma disposed in an upper portion of the cavity, and an ion current collector disposed within the cavity at an opposite side of the cavity below the ion angle selection grid. The ion angle selection grid includes an ion angle selection substrate and a plurality of through openings extending through the ion angle selection substrate, where each of the plurality of through openings has a depth into the ion angle selection substrate and a width orthogonal to the depth, where a ratio of the depth to the width is greater than or equal to 40.