CMOS Image Sensor Gate Width With Vertical Penetration Contacts
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Solution Overview
Problem
Current CMOS image sensors face challenges in achieving improved electric characteristics, such as increased integration density and reduced cross-talk between unit pixel regions, while maintaining effective photoelectric conversion properties.
Innovation Solution
The image sensor design incorporates a penetration structure with specific patterns and materials, including metal silicides, to enhance electrical connections and prevent cross-talk, while optimizing the layout of gate patterns and isolation patterns to improve electric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate pattern width is increased to improve electric characteristics, then the photoelectric conversion area is reduced, but electric characteristics are improved
Solution Approach 1:
The penetration structure extends vertically from the first interconnection layer through the second interconnection layer to contact the gate pattern, creating a three-dimensional electrical connection path. This vertical dimension allows the gate pattern to maintain a larger width for improved electric characteristics while the penetration structure provides the necessary electrical connection without occupying horizontal photoelectric conversion area.
Solution Approach 2:
The penetration structure acts as an intermediary element that bridges the gate pattern and the interconnection layers. It provides electrical connection between these components without requiring the gate pattern to be narrow, thus resolving the conflict between gate width and photoelectric conversion area.
2Quantity of substance
If penetration structures are added to improve electrical connections, then integration density increases, but device complexity increases
Solution Approach 1:
The penetration structure serves multiple functions simultaneously: it provides electrical connection between interconnection layers, maintains structural integrity across multiple layers, and enables the gate pattern to have optimized dimensions for electric characteristics. This multi-functionality increases integration density without proportionally increasing device complexity.
3Reliability
If isolation patterns are used to reduce cross-talk between unit pixel regions, then photoelectric conversion efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The device is divided into discrete unit pixel regions separated by isolation patterns. This segmentation prevents cross-talk between adjacent pixels, improving photoelectric conversion efficiency by ensuring that electrical signals from one pixel do not interfere with neighboring pixels. The isolation patterns create independent electrical zones that can be manufactured using standard semiconductor fabrication processes.
Data Source
AI summary
An image sensor may include a substrate having first and second surfaces opposite to each other and including unit pixel regions and impurity regions near the first surface, a device isolation pattern provided on the first surface to define the impurity regions, and an interconnection layer including an insulating layer covering the first surface of the substrate, interconnection lines on the insulating layer, and a penetration structure penetrating the insulating layer. The penetration structure may include a first pattern connected to one of the impurity regions and in contact with at least a portion of the device isolation pattern, a second pattern provided on the first pattern and in contact with the interconnection lines, and a third pattern provided between the first and second patterns. A top surface of the first pattern may be higher than that of the device isolation pattern.