Tiled Radiation Detector Wafer Utilization
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Solution Overview
Problem
Current digital X-ray imaging systems using amorphous silicon technology face limitations in achieving high resolution and low electronic noise, while crystalline silicon technology, which offers better performance, is costly and inefficient due to the need for multiple wafers and complex fabrication processes for non-rectangular panels.
Innovation Solution
The development of a flat panel X-ray detector with a tiled arrangement of imager panels, including wedge-shaped and rectangular tiles, allows for the creation of non-rectangular active areas, maximizing the use of crystalline silicon wafers and reducing waste, thereby lowering fabrication costs and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon technology is used for large area X-ray panels, then manufacturing cost is reduced and large area capability is achieved, but resolution and electronic noise performance deteriorate
Solution Approach 1:
The patent divides the large area detector into multiple smaller rectangular sub-detectors (tiles) that can be independently fabricated on separate crystalline silicon wafers. Each sub-detector maintains high resolution and low noise performance characteristic of c-Si technology, while the segmented approach enables modular assembly into large area configurations, thus achieving both high performance and manufacturability.
2Manufacturing precision
If crystalline silicon wafers are used to fabricate non-rectangular panels, then resolution and electronic noise performance are improved, but fabrication complexity and cost increase due to multiple wafers and tiling
Solution Approach 1:
The patent segments the non-rectangular detector design into rectangular sub-detectors that can be fabricated using standard wafer processes, avoiding the need for complex non-rectangular wafer fabrication. The rectangular tiles are then arranged and connected to form the desired non-rectangular overall shape, simplifying the fabrication process while maintaining high performance.
Solution Approach 2:
The patent combines multiple rectangular sub-detectors into a single integrated non-rectangular detector system through electrical connections and mechanical assembly. This merging approach allows the system to achieve the desired non-rectangular geometry and large active area while utilizing the advantages of standard rectangular wafer fabrication processes for each individual tile.
3Manufacturing precision
If multiple crystalline silicon wafers are tiled to form non-rectangular panels, then high resolution performance is achieved, but material waste increases and fabrication efficiency decreases
Solution Approach 1:
The patent segments the detector into rectangular tiles that can be optimally cut from standard circular silicon wafers, maximizing wafer utilization. By using rectangular geometries for individual tiles rather than attempting to fabricate complex non-rectangular shapes directly on wafers, the design enables more efficient wafer cutting patterns and reduces material waste.
Solution Approach 2:
The patent changes the geometric parameters of the individual detector units from non-rectangular to rectangular shapes, which are more compatible with standard wafer fabrication and cutting processes. This parameter change allows for more efficient material utilization during wafer dicing and assembly, reducing material waste while maintaining the desired overall non-rectangular detector geometry through the arrangement of rectangular tiles.
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 the fabrication of non-rectangular light imager panels with comparable active areas to rectangular panels using fewer crystalline silicon wafers, reducing material waste and fabrication costs, while maintaining high resolution and low noise performance.
Implementation Method 1
The scintillator of the detector converts the higher-energy X-ray radiation to lower-energy light photons
Implementation Method 2
a light imager layer configured to convert the light photons into electrons
Data Source
AI summary
The present approaches relate to the fabrication of non-rectangular (e.g., non-square) light imager panels having comparable active areas to rectangular light imager panels but manufactured using fewer c-Si wafers. Such light imager panels may be generally squircle shaped (e.g., a square or rectangle with one or more rounded corners and may be manufactured using conventional crystalline silicon (c-Si) wafers, such as 8″ wafers.