Solid-State Imaging Device Using Cu-Cu Bonding to Reduce TSV Area
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Solution Overview
Problem
Conventional asynchronous solid-state imaging devices face challenges in improving resolution due to the increased area of through silicon vias (TSVs) as the number of pixels increases, limiting the space for pixel arrays.
Innovation Solution
The implementation of first connections via Cu-Cu bonding between light-receiving circuits and address event detection circuits, reducing the area of via placement regions and enabling higher pixel density, while maintaining fast signal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to improve resolution, then the resolution is improved, but the area occupied by through silicon vias (TSVs) increases, limiting the space for pixel arrays
Solution Approach 1:
The patent transitions from planar TSV connections to three-dimensional Cu-Cu bonding connections between stacked substrates. By moving connection points to the bonding interface between substrates rather than requiring extensive TSVs within a single substrate, the via placement area is significantly reduced, allowing more space for pixel arrays while maintaining high pixel density
Solution Approach 2:
The imaging device is divided into multiple stacked substrates (first substrate with photoelectric conversion elements, second substrate with reading circuits, third substrate with address event detection circuits). This segmentation allows connection points to be distributed across multiple layers and bonding interfaces, reducing the concentration of via placement area in any single substrate and enabling higher resolution
2Speed
If through silicon vias (TSVs) are used for connecting circuits, then signal transfer is achieved, but the via placement area becomes large, reducing pixel array space
Solution Approach 1:
The patent introduces bonding pads and Cu-Cu bonding interfaces as intermediary connection structures between stacked substrates. These intermediaries provide efficient electrical connection points that require minimal area compared to TSVs, while maintaining fast signal transfer capability through direct copper-to-copper bonding at the substrate interfaces
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 configuration allows for higher pixel density and faster signal processing, enhancing the resolution and processing speed of the solid-state imaging device.
Implementation Method 1
first connections via Cu-Cu bonding between light-receiving circuits and address event detection circuits
Implementation Method 2
n first photoelectric conversion devices periodically arranged in the first semiconductor substrate and generating first electric charge signals
Data Source
Figure 1~2
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AI summary
A solid-state imaging device (200) according to the present disclosure includes a light-receiving substrate (201), a circuit board (202), and a plurality of first connections (270). The light-receiving substrate (201) includes a plurality of light-receiving circuits (211) provided with photoelectric conversion elements. The circuit board (202) is directly bonded to the light-receiving substrate (201) and includes a plurality of address event detection circuits (231) that detects individual changes in voltages output from the photoelectric conversion elements of the plurality of light-receiving circuits (211). The plurality of first connections (270) is provided at a joint (203) between the light-receiving substrate (201) and the circuit board (202) to electrically connect the light-receiving circuits (211) and the address event detection circuits (231) corresponding to each other.