Multi-layer X-ray Grating Self-Alignment Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current X-ray phase-contrast imaging technologies face challenges in fabricating high-resolution, multi-layer high-aspect ratio X-ray gratings for compact systems and higher energy applications, particularly due to stringent requirements for grating feature sizes and aspect ratios, which affect image quality and detail information, especially when trying to achieve larger field-of-view imaging.
Innovation Solution
A multi-layer high-aspect ratio X-ray grating fabrication method involving a seed layer, patterned non-X-ray absorbing layers, and X-ray absorbing layers, with self-alignment through backside radiation exposure, such as UV, EUV, or IR exposure, using materials like gold, platinum, or indium, and a combination of SU-8 photoresist and LIGA processes to create periodic structures for improved alignment and aspect ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-layer grating fabrication methods are used, then manufacturing process is simpler, but manufacturing precision and aspect ratio are insufficient for high-resolution imaging
Solution Approach 1:
The grating structure is divided into multiple layers, with each layer containing alternating absorbing and non-absorbing regions. This segmentation allows achieving high aspect ratios and precise feature sizes by stacking multiple simpler patterns rather than attempting to fabricate a single complex high-aspect-ratio structure in one step.
Solution Approach 2:
The fabrication approach transitions from two-dimensional planar patterns to three-dimensional multi-layer stacked structures. By adding the vertical dimension through multiple stacked layers, the grating achieves high aspect ratios while maintaining precise lateral feature sizes defined by the underlying 2D patterns.
2Manufacturing precision
If alignment precision is increased to improve imaging quality, then image quality improves, but alignment process complexity and difficulty increase
Solution Approach 1:
The patterned non-absorbing layers serve as self-aligned alignment references for subsequent absorbing layer patterning. The self-aligned process uses the previously formed patterns as built-in alignment features, eliminating the need for external alignment measurement and control systems, thereby achieving high precision without increased operational complexity.
3Measurement precision
If grating aspect ratio is increased for higher resolution, then imaging resolution improves, but mechanical stability and fabrication feasibility deteriorate
Solution Approach 1:
The high aspect ratio grating is segmented into multiple lower aspect ratio layers stacked vertically. Each layer maintains mechanical stability with its own patterned non-absorbing structures providing support, while collectively achieving the desired high aspect ratio. This segmentation distributes mechanical stress across multiple layers rather than concentrating it in a single high-aspect-ratio structure.
4Area of stationary object
If field-of-view is increased for larger imaging area, then imaging coverage improves, but grating fabrication area and complexity increase
Solution Approach 1:
The large area grating is divided into multiple stacked layers, each covering the same field-of-view area but with simplified individual patterns. This segmentation allows fabricating large area gratings by stacking multiple smaller, easier-to-fabricate layers rather than attempting to pattern a single large area structure, thereby reducing overall fabrication complexity.
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 method enables the production of high-resolution, high-aspect ratio X-ray gratings with improved alignment accuracy and mechanical stability, facilitating higher contrast and sensitivity in X-ray phase-contrast imaging, especially for larger field-of-view applications without the need for specialized facilities, thus enhancing imaging quality and resolution.
Implementation Method 1
fabricating the at least one patterned non-X-ray absorbing layer includes exposing the grating to backside radiation exposure
Implementation Method 2
at least one X-ray absorbing layer made from gold, platinum, nickel, lead, selenium, bismuth, tungsten, or indium
Data Source
AI summary
The disclosure is directed at a multi-layer, high-aspect ratio X-ray grating apparatus and method of fabrication. In one embodiment, the disclosure may include a self-alignment methodology, or process, combined with a multiple layer structure fabrication. The grating may include a substrate with a seed layer on top. The grating further includes at least one patterned non-X-ray absorbing layer and at least one X-ray absorbing layer atop the seed layer.