Image Sensor Interconnect Layout for Higher Pixel Resolution
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Solution Overview
Problem
Current image sensors face challenges in achieving high resolution due to limitations in their conductive structures and interconnection methods, which affect the efficiency of signal transmission and photocharge management across pixel regions.
Innovation Solution
The image sensor design incorporates a conductive structure with a connection portion extending parallel to the substrate surface and vertically penetrating contacts coupled to floating diffusion regions, enhancing electrical connectivity and signal output across unit pixel regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional conductive structures with vertical connections are used, then the structure is simple, but the signal transmission efficiency and resolution are limited
Solution Approach 1:
The conductive structure transitions from a conventional vertical connection to a three-dimensional configuration with a connection portion extending parallel to the substrate surface and contacts extending vertically. This dimensional change enables improved signal transmission efficiency and photocharge management while achieving enhanced resolution without excessive complexity
2Reliability
If contacts are spaced apart with pixel isolation pattern interposed, then signal isolation between pixels is improved, but electrical connectivity within pixel groups becomes more complex
Solution Approach 1:
The connection portion acts as an intermediary element that horizontally connects multiple vertically extending contacts. This intermediary structure enables effective signal isolation between adjacent pixels through the pixel isolation pattern while maintaining efficient electrical connectivity within pixel groups through the horizontal connection portion
3Power
If the connection portion extends parallel to the substrate surface, then voltage output from photoelectric conversion regions is enhanced, but the interconnection layer complexity increases
Solution Approach 1:
The connection portion extends parallel to the substrate surface in the horizontal direction, creating a three-dimensional conductive pathway. This dimensional configuration enhances voltage output from photoelectric conversion regions by providing an extended connection path while distributing the interconnection complexity across multiple dimensions rather than concentrating it vertically
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 increases the resolution of the image sensor by improving the electrical connection and signal transmission efficiency, allowing for better photocharge management and enhanced voltage output from photoelectric conversion regions.
Implementation Method 1
Each of the unit pixel regions includes a photodiode which is used to convert an incident light to an electric signal
Data Source
AI summary
An image sensor includes a substrate having a first surface and a second surface that are opposite to each other. The substrate including a plurality of unit pixel regions having photoelectric conversion regions and floating diffusion regions disposed adjacent to the first surface. A pixel isolation pattern is disposed in the substrate and is configured to define the plurality of unit pixel regions. An interconnection layer is disposed on the first surface of the substrate. The interconnection layer includes a conductive structure having a connection portion that extends parallel to the first surface of the substrate and is spaced apart from the first surface of the substrate. Contacts extend vertically from the connection portion towards the first surface of the substrate. Each of the contacts are spaced apart from each other with the pixel isolation pattern interposed therebetween. The contacts are coupled to the floating diffusion regions, respectively.