Interposer-Tiled X-Ray Sensor Layout Without CMOS Stitching
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Solution Overview
Problem
Conventional large-scale CMOS X-ray radiation sensors face issues with high yield loss, low area utilization, and increased manufacturing complexity due to process defects and the need for stitching, leading to high device costs.
Innovation Solution
The design incorporates a direct or indirect X-ray conversion layer with small pixel sensor arrays and interposers, allowing for four-side buttable X-ray sensor devices, which eliminates the need for stitching and improves yield by using silicon interposers to electrically couple pixel sensor arrays to electrodes or photodiodes, enabling efficient area utilization and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If large area CMOS sensors are built using standard fabrication approaches, then the sensor area is increased, but the yield loss increases due to process defects
Solution Approach 1:
The patent divides the large sensor area into multiple smaller sensor tiles that can be independently fabricated and tested. Each tile is then bonded together to form the complete large sensor array. This segmentation allows standard fabrication processes to be used for smaller, more manageable tiles while achieving the desired large sensor area, thereby reducing yield loss associated with fabricating one large defective die.
Solution Approach 2:
The patent implements a modular architecture where multiple sensor tiles are nested or stacked together through bonding processes. The tiles are arranged in a configuration that allows them to be combined into a large sensor area while maintaining the integrity of each individual tile. This nesting approach enables the system to achieve large sensor dimensions without requiring a single large-wafer fabrication process that would be prone to yield losses.
2Area of stationary object
If large area sensors are built, then the detector area is increased, but the wafer area utilization decreases
Solution Approach 1:
By segmenting the large sensor into smaller tiles, the patent enables more efficient use of wafer area. Multiple smaller tiles can be fabricated from a single wafer, and then bonded together to create the final large sensor. This approach increases the total number of functional detector elements that can be produced from each wafer, thereby improving wafer area utilization compared to fabricating a single large sensor.
Solution Approach 2:
The patent transitions from a two-dimensional wafer layout to a three-dimensional stacked or bonded configuration. By arranging multiple sensor tiles in vertical or multi-dimensional arrangements through bonding, the system achieves a large total detector area while using a relatively small wafer area for fabrication. This dimensional transformation allows for high area utilization efficiency.
3Area of stationary object
If large sensor area is built, then the detector area is increased, but the manufacturing complexity increases due to stitching requirements
Solution Approach 1:
The patent segments the large sensor into smaller tiles that can be fabricated using standard processes without requiring stitching. Each tile is independently manufactured and then bonded together, eliminating the need for complex stitching operations that would be required to create a single large continuous sensor array. This segmentation significantly reduces manufacturing complexity while achieving the desired large detector area.
Solution Approach 2:
The patent extracts the stitching process from the manufacturing methodology by using separate sensor tiles that are bonded together instead of stitching continuous patterns. This extraction eliminates the complex stitching operations and replaces them with simpler tile bonding processes, thereby reducing manufacturing complexity while maintaining the ability to create large sensor areas.
4Area of stationary object
If large area CMOS sensors are built, then the sensor area is increased, but the device cost increases
Solution Approach 1:
By segmenting the large sensor into smaller tiles, the patent reduces the cost of manufacturing. Each tile can be fabricated using standard processes with lower defect rates and better yield, reducing the overall cost compared to fabricating a single large sensor. The modular approach also allows for more efficient use of fabrication resources and reduces the need for expensive stitching operations, thereby lowering device cost while achieving large sensor area.
Solution Approach 2:
The nested or stacked configuration of multiple sensor tiles allows for cost-effective manufacturing by enabling parallel production and reducing the need for expensive single-large-die fabrication processes. The modular tile structure facilitates standardized manufacturing procedures that can be scaled efficiently, reducing overall device cost while achieving the required large sensor area through combination of multiple standardized units.
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 simplifies the manufacturing process, improves yield, and reduces costs by allowing the construction of large X-ray radiation detectors without stitching, effectively utilizing the wafer area and minimizing the impact of defects, thus providing a cost-effective solution for medical diagnostics.
Implementation Method 1
a direct X-ray conversion layer, a plurality of electrodes to provide an electric charge in response to an interaction of an X-ray photon within the X-ray conversion layer
Data Source
AI summary
An X-ray radiation sensor device may include a direct X-ray conversion layer, a plurality of electrodes to provide an electric charge in response to an interaction of an X-ray photon within the direct X-ray conversion layer, a plurality of pixel sensor arrays, and at least one interposer. The direct X-ray conversion layer and the plurality of electrodes are disposed on the top surface of the interposer(s). The plurality of the pixel sensor arrays is disposed on the bottom surface of the interposer(s), and the interposer(s) is configured to electrically couple each of the pixel sensor arrays to a respective portion of the plurality of electrodes.