Conductive Via Interconnects for Tileable Photo-Detector Arrays
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Solution Overview
Problem
Current CT systems are limited in expanding the number of photo-detector elements due to physical constraints from electrical signal readout, particularly in the z-direction, as they require narrow metal lines and wire bonding, which restricts the size and growth of the detector array.
Innovation Solution
The implementation of conductive vias through the substrate allows for electrical connections between the active areas of semiconductor devices on one surface to the other, eliminating the need for edge connections and enabling the expansion of photo-detector arrays in the z-direction by connecting all signals on the underside of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow metal lines and wire bonding are used for signal readout, then electrical connections can be established, but the detector array size is limited in the z-direction
Solution Approach 1:
The patent transitions from two-dimensional edge connections to three-dimensional bulk connections by forming conductive vias through the substrate. This allows electrical connections to be made at the bottom surface of the substrate rather than at the edges, enabling detector arrays to expand in the z-direction without being constrained by edge connection limitations.
Solution Approach 2:
The patent introduces conductive vias as intermediary structures that penetrate the substrate to establish electrical connections. These vias serve as mediators between the active areas on the top surface and the connection structures on the bottom surface, eliminating the need for narrow metal lines and wire bonding at the edges.
2Measurement precision
If more detector elements are added to increase data collection, then measurement accuracy and speed improve, but the physical constraints of edge connections prevent array expansion
Solution Approach 1:
By moving connections from the two-dimensional edge to the three-dimensional bulk via conductive vias, the patent enables detector arrays to expand in multiple directions including the z-direction. This removes the physical constraint that previously limited array expansion and allowed only lateral additions of detector elements.
Solution Approach 2:
The conductive via structure provides a universal connection method that works for detector arrays of any size and configuration. Unlike edge connections that require specific boundary locations, vias can be distributed throughout the substrate, allowing flexible and scalable array designs that accommodate increasing numbers of detector elements.
3Area of stationary object
If detector arrays are expanded by placing individual arrays adjacent to each other, then the imaging plane size increases, but the z-direction expansion is blocked by wire connection areas
Solution Approach 1:
The patent moves the connection interface from the two-dimensional edge to the three-dimensional bulk through the substrate. This allows detector arrays to be stacked or expanded in the z-direction without requiring edge clearance for wire bonding, as all connections are made at the bottom surface through conductive vias.
Solution Approach 2:
The patent enables modular detector array construction where individual arrays can be independently fabricated and then combined. The conductive via structure allows each array to maintain its own connection integrity while being part of a larger expanded array, facilitating modular expansion in both lateral and vertical directions.
Data Source
AI summary
There is disclosed a photo-detector array including a plurality of sub-arrays of photo-detectors, the photo-detectors of each sub-array being formed on a substrate with an active area of each photo-detector being formed on a surface of the substrate, there further being formed for each photo-detector a conductive via through the substrate from an upper surface thereof to a lower surface thereof to connect the active area of each photo-detector to the lower surface of the substrate, wherein a plurality of said sub-arrays of photo-detectors are placed adjacent to each other in a matrix to form the photo-detector array. An imaging system comprising: a radiation detector including such a photo detector array, a radiation source facing the radiation detector, and means for controlling the radiation detector and the radiation source is also disclosed. A method for making such an array is also disclosed.