Movable Beam Blockers for Ion Extraction Uniformity
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Solution Overview
Problem
Current ion extraction technologies face challenges in achieving uniform ion angular distributions, especially at low rf power and plasma density, which affects processing applications like controlled etching and magnetic random memory structures, due to discrepancies in angular distributions from different extraction slits.
Innovation Solution
The use of movable beam blockers in the ion extraction optics system, which includes an extraction plate with inner and outer slits, allows for adjustment of slit distances and angles to mitigate differences in ion angular distributions by rotating and moving the blockers to balance plasma density and ion beam currents across different slits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of extraction slits is increased to increase ion beam current, then processing throughput is improved, but differences in angular distributions of ion beamlets from different slits become more pronounced
Solution Approach 1:
The patent applies local quality by introducing beam blockers that can be independently adjusted for each extraction slit. This allows each slit to have customized blocking ratios tailored to its specific angular distribution characteristics, thereby equalizing the overall ion angular distribution across all slits while maintaining high processing throughput
Solution Approach 2:
The beam blockers are designed to be movable and adjustable, allowing dynamic optimization of the ion beam extraction. The blockers can be positioned at different distances from the extraction plate and adjusted to achieve desired blocking ratios, enabling the system to adapt to varying operational conditions while maintaining uniform angular distribution
2Power
If rf power and plasma density are decreased, then certain processing applications are enabled, but discrepancies in angular distributions from different extraction slits become more pronounced
Solution Approach 1:
At lower rf power and plasma density, the beam blockers provide localized adjustment capability for each extraction slit. This allows compensation for the increased discrepancies in angular distributions that occur at low power, enabling uniform ion angular distribution to be maintained even when operating at reduced power levels for specific processing applications
3Manufacturing precision
If beam blockers are introduced to equalize ion angular distributions, then processing uniformity is improved, but device complexity increases
Solution Approach 1:
The beam blockers are segmented into multiple independent components, each associated with a specific extraction slit. This segmentation allows for independent adjustment of each blocker to achieve the desired blocking ratio, simplifying the control strategy while effectively equalizing ion angular distributions across all slits
Solution Approach 2:
The beam blockers are designed to be adjustable by the operator based on measured angular distributions. The system enables self-service optimization where the user can adjust blocker positions to achieve uniform ion angular distribution without requiring complex automated control systems
Data Source
AI summary
Disclosed herein are approaches for adjusting extraction slits of an extraction plate using a set of adjustable beam blockers. In one approach, an ion extraction optics may include an extraction plate including a first opening and a second opening, and a first beam blocker extending over the first opening and a second beam blocker extending over the second opening. Each of the first and second beam blockers may include an inner slit defined by a first distance between an inner edge and the extraction plate, and an outer slit defined by a second distance between an outer edge and the extraction plate, wherein the first and second beam blockers are movable to vary at least one of the first distance and the second distance. As a result, extraction through the inner and outer slits of ion beamlets characterized by similar mean angles may be achieved.