X-ray Phase Contrast Grating Adaptation via Segmented Silicon Etching
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Solution Overview
Problem
Existing methods for producing X-ray phase contrast gratings struggle to adapt the slat orientation to the local radiation direction, leading to suboptimal imaging precision due to limitations in etching processes and material distribution.
Innovation Solution
A method involving multiple etching steps on a silicon substrate to create a high aspect ratio of boreholes and gaps, allowing for precise control over the orientation and spacing of seed structures, which are then filled with X-ray absorbing material to form a microstructure component that can be bent to align with the radiation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional etching processes are used to produce phase contrast gratings, then the manufacturing process is simple, but the lamellae cannot be angled to adapt to local radiation direction
Solution Approach 1:
The invention divides the continuous grating structure into discrete segments by introducing periodic gaps between lamellae groups. These gaps are created through selective removal of sacrificial material, allowing different grating sections to be independently oriented and angled to match local radiation directions while maintaining overall grating functionality
Solution Approach 2:
The invention introduces angular orientation as an additional degree of freedom beyond the traditional planar grating structure. By angling lamellae groups relative to each other in three-dimensional space, the grating can adapt to radially diverging X-ray beams from point sources, transforming a two-dimensional planar structure into a three-dimensional angularly-resolved structure
2Measurement precision
If the grating thickness is increased to improve imaging precision, then the imaging precision improves, but the mechanical stability decreases
Solution Approach 1:
The grating is segmented into multiple lamellae groups with periodic gaps between them. This segmentation reduces the overall grating thickness required for adequate imaging precision while maintaining mechanical stability, as each individual lamellae group can be thinner yet collectively provide the necessary imaging performance
Solution Approach 2:
The invention employs thin film structures for the lamellae groups that are sufficiently thin to maintain mechanical flexibility and stability, yet precisely controlled in thickness to achieve the required imaging precision. The periodic gaps further reduce material usage while maintaining structural integrity
3Measurement precision
If the lamellae are made thinner to improve resolution, then the resolution improves, but the manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The invention introduces sacrificial material as an intermediary element that defines the spacing and positioning of lamellae groups. This sacrificial material serves as a template during manufacturing, making it easier to control the thickness and spacing of thin lamellae structures. After the lamellae are formed, the sacrificial material is selectively removed to create periodic gaps
Solution Approach 2:
The sacrificial material is deposited and patterned beforehand to establish the desired lamellae spacing and thickness before the actual grating structures are formed. This preliminary structuring simplifies subsequent manufacturing steps and improves precision in creating thin, evenly-spaced lamellae
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 enhances the mechanical stability and imaging precision of the phase contrast grating, enabling it to be adapted to the local radiation direction, thereby improving the contrast and quality of X-ray images.
Implementation Method 1
In a third etching step, an anisotropic etching medium – in particular an etching solution – is flushed alternately from both surfaces of the silicon substrate through the drill holes
Implementation Method 2
The etching medium is flushed alternately through the drill holes until the drill holes, arranged side by side in the first substrate direction, merge to form a gap running in the first substrate direction
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a method for producing a microstructured component (4), a microstructured component (4) and an X-ray device (1). A plurality of point-like seed structures (22) are introduced into a first surface (23) of a disk-like silicon substrate (26) in a grid (28) defined along a first and a second substrate direction (S1,S2) perpendicular to it, and the seed structures (22) are extended to boreholes in the depth direction (10) of the silicon substrate (26) in a first etching step (40).A second surface (52) of the silicon substrate (26) is then at least partially removed in a second etching step (50) to open the boreholes from the back, and in a third etching step (60) an anisotropically acting etching medium is flushed alternately from both surfaces (24, 52) of the silicon substrate (26) through the boreholes, so that the boreholes arranged next to each other in the first substrate direction (S1) connect to form a gap (62) running in the first substrate direction (S1).