Interferometer Feedback for Energetic Beam Topography Control
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Solution Overview
Problem
Current energetic beam processes lack effective control over surface topography creation, particularly in terms of depth, shape, and roughness, due to the absence of real-time feedback mechanisms that can simultaneously monitor and adjust the processing of specimens with varying surface profiles.
Innovation Solution
Integration of a Michelson-type interferometer with an energetic particle column, such as a Focused Ion Beam tool, allows for simultaneous exposure of a specimen to energetic particles and measurement of surface heights, enabling real-time feedback control of the ion beam to achieve precise topography creation by adjusting the ion beam's focus, steering, and dwell time based on interferometric data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional energetic beam processes are used without real-time feedback, then the process is simpler and faster, but the control over surface topography (depth, shape, roughness) is poor
Solution Approach 1:
The patent combines the interferometer (measurement device) with the energetic beam tool (processing device) into an integrated system. The interferometer is positioned to illuminate the specimen surface simultaneously with the beam exposure, allowing real-time topography measurement during processing without requiring separate measurement steps or specimen transfer between devices.
Solution Approach 2:
The system uses the interferometer to continuously monitor surface topography changes during energetic beam processing and feeds this information back to the beam control system. This real-time feedback enables dynamic adjustment of beam parameters (such as beam current, scan speed, or focal position) to achieve precise control over surface depth, shape, and roughness.
2Measurement precision
If real-time feedback control is implemented, then the manufacturing precision of surface topography is improved, but the measurement and control complexity increases
Solution Approach 1:
The interferometer is pre-positioned and aligned with the energetic beam path before processing begins. The optical setup is configured in advance to illuminate the entire specimen surface or the specific area of interest, so that measurement is already prepared and ready to capture topography changes as they occur during beam exposure, without requiring real-time alignment adjustments.
Solution Approach 2:
The interferometer acts as an intermediary measurement device that indirectly captures surface topography information through optical interference patterns. Instead of directly measuring surface height with complex contact probes or other intrusive methods, the interferometer uses light interference to non-contactingly detect surface profile changes, simplifying the measurement process while maintaining high precision.
3Productivity
If specimens are transferred between processing and metrology tools, then specialized equipment can be used for each function, but the processing time and operational complexity increase
Solution Approach 1:
The patent merges the metrology function (interferometer) and the processing function (energetic beam tool) into a single integrated apparatus. Both functions operate on the specimen simultaneously within the same device, eliminating the need to physically transfer the specimen between separate processing and measurement equipment, thereby improving productivity and simplifying operation.
Solution Approach 2:
The integrated system performs multiple functions (surface processing and topography measurement) within a single device. The apparatus is designed to be multi-functional, allowing it to both modify the specimen surface with the energetic beam and simultaneously monitor the resulting topography changes with the interferometer, reducing the need for multiple specialized tools and specimen handling steps.
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 approach enables precise control over surface topography, allowing for the creation of desired profiles on planar, multi-planar, faceted, curved, and irregular surfaces without the need for transferring specimens between processing and metrology tools, improving the accuracy and efficiency of energetic beam processes.
Implementation Method 1
an interferometer, integrated with an energetic particle column, is used to monitor and provide feedback control of the depth, shape and/or roughness of features created at the surface
Implementation Method 2
Energetic beam processes utilize tools that generate, focus, and direct beams comprised of energetic particles, for example, photons, ions, electrons and/or accelerated neutral particles, to modify and/or analyze the surface of the specimen
Data Source
AI summary
Methods and apparatus whereby an optical interferometer is utilized to monitor and provide feedback control to an integrated energetic particle column, to create desired topographies, including the depth, shape and/or roughness of features, at a surface of a specimen. Energetic particle columns can direct energetic species including, ions, photons and/or neutral particles to a surface to create features having in-plane dimensions on the order of 1 micron, and a height or depth on the order of 1 nanometer. Energetic processes can include subtractive processes such as sputtering, ablation, focused ion beam milling and, additive processes, such as energetic beam induced chemical vapor deposition. The integration of interferometric methods with processing by energetic species offers the ability to create desired topographies at surfaces, including planar and curved shapes.