Stacked Imaging Sensor Readout Using Organic Semiconductor Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In imaging devices with a three-dimensional structure, stacking semiconductor chips with insufficient consideration leads to increased chip size and hindrances in miniaturization of area per pixel due to electrical connections, which is undesirable for maintaining current chip size and pixel density.
Innovation Solution
An imaging device is designed with a first semiconductor substrate having pixels with a photoelectric conversion element and a floating diffusion, and a semiconductor layer formed of organic material on the substrate via an insulating film, including a readout circuit unit to read and output pixel signals, allowing for efficient electrical connection without increasing chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three semiconductor substrates are stacked with insufficient consideration, then electrical connections can be established, but chip size increases and miniaturization of area per pixel is hindered
Solution Approach 1:
The patent transitions from planar electrical connections to three-dimensional vertical connections by stacking semiconductor substrates. The readout circuit unit is positioned on a different layer (second substrate) than the pixel array (first substrate), enabling electrical connections through the thickness direction rather than requiring lateral expansion on the same plane. This dimensional change allows compact chip size while maintaining reliable electrical connections.
Solution Approach 2:
The patent implements a nested structure where the readout circuit unit is embedded within the stacked substrate configuration. The first substrate containing pixels is stacked with a second substrate containing the readout circuit unit, creating a nested three-dimensional architecture. This nesting approach integrates multiple functional units within a compact volume, preventing chip size increase while ensuring proper electrical connections between layers.
2Reliability
If three semiconductor substrates are stacked with insufficient consideration, then electrical connections can be established, but miniaturization of area per pixel is hindered
Solution Approach 1:
By moving the readout circuit unit to a separate stacked layer rather than placing it laterally adjacent to pixels on the same substrate, the patent frees up pixel area. The vertical stacking arrangement in the thickness direction eliminates the need for lateral space that would otherwise be required for circuitry, thereby enabling miniaturization of the area per pixel while maintaining electrical connection reliability.
Solution Approach 2:
The patent segments the imaging device into distinct functional layers: the first substrate dedicated to pixel arrays and the second substrate dedicated to the readout circuit unit. This segmentation separates pixel functions from circuit functions into different spatial domains (different substrates), allowing each to be optimized independently. The pixel area can be minimized without compromising circuit functionality, as the circuit resides on a separate stacked layer.
3Productivity
If readout circuit unit is integrated on the same substrate, then signal processing can be performed, but chip size increases
Solution Approach 1:
The patent resolves the space requirement for signal processing by implementing the readout circuit unit on a stacked substrate rather than on the same substrate as the pixel array. This vertical separation in the thickness direction allows the readout circuit to perform signal processing functions without occupying lateral chip area, thereby maintaining compact chip size while ensuring efficient signal processing capability.
Solution Approach 2:
The readout circuit unit is nested within the stacked substrate structure, integrated into the three-dimensional architecture rather than expanding the two-dimensional chip footprint. This nested arrangement embeds the signal processing functionality within the vertical stack, allowing signal processing to occur without increasing the lateral dimensions of the chip.
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 enables miniaturization of the imaging device without hindering area per pixel density, maintaining current chip size while improving signal processing efficiency and reducing noise in image data.
Implementation Method 1
a first semiconductor substrate provided with pixels including a photoelectric conversion element
Implementation Method 2
floating diffusion that temporarily holds a charge output from the photoelectric conversion element
Data Source
AI summary
An imaging device according to an embodiment of the present disclosure includes: a first semiconductor substrate (100) provided with pixels including a photoelectric conversion element (PD) and floating diffusion (FD) that temporarily holds a charge output from the photoelectric conversion element (PD); and a semiconductor layer (200Y) provided on the first semiconductor substrate (100) via an insulating film (123), the semiconductor layer (200Y) including a readout circuit unit (539) that reads out the charge held in the floating diffusion (FD) and outputs a pixel signal, in which the semiconductor layer (200Y) is formed of an organic semiconductor material.