Stacked Imaging Sensor Via Layout for Smaller Pixels and Lower Noise
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Solution Overview
Problem
There is a limit to the downsizing and miniaturization of imaging devices with a three-dimensional structure, which restricts further advancements in device miniaturization and pixel density.
Innovation Solution
The proposed solution involves an imaging device with a first semiconductor substrate having a photoelectric conversion element and a second semiconductor substrate stacked with an interlayer insulating film, where a via penetrates the insulating film to electrically connect the substrates, allowing for improved layout flexibility and miniaturization by eliminating the need for through electrodes that penetrate the semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If through electrodes penetrating the semiconductor layer are used to connect substrates, then electrical connection between substrates is achieved, but device size cannot be further reduced and layout flexibility is limited
Solution Approach 1:
The patent transitions from planar through-electrode connections to three-dimensional stacked substrate architecture with via connections through the interlayer insulating film. This dimensional change allows electrical connection without penetrating the semiconductor layer, enabling further miniaturization and improved layout flexibility of the imaging device
2Area of stationary object
If through electrodes are used for substrate connection, then electrical connection is established, but the area available for transistor formation is reduced
Solution Approach 1:
The patent segments the connection structure into two parts: vias through the interlayer insulating film for electrical connection, and the semiconductor layer remaining intact for transistor formation. This segmentation allows the transistor formation area to be maximized while still achieving substrate electrical connection, thereby reducing signal noise and improving reliability
Data Source
AI summary
Provided is an imaging device including: a first semiconductor substrate provided with a photoelectric conversion element, a second semiconductor substrate stacked on the first semiconductor substrate with an interlayer insulating film interposed therebetween and provided with a pixel circuit that reads out charges generated in the photoelectric conversion element as a pixel signal, and a via that penetrates the interlayer insulating film and electrically connects a first surface of the first semiconductor substrate facing the second semiconductor substrate and at least a part of a second surface of the second semiconductor substrate facing the first surface.