Stacked Capacitor Layout in Image Sensors for Stable Signal Transfer
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Solution Overview
Problem
Current image sensors face challenges in achieving stable processing and efficient signal transmission due to complex capacitor structures and wiring configurations, which can lead to instability and reduced performance in image sensing applications.
Innovation Solution
The proposed image sensor design includes a substrate with a photoelectric converter, transistors, and a capacitor structure with multiple electrodes and contact plugs, which are electrically connected to ensure stable signal transmission and processing, featuring a capacitor layer between metal layers and connectors to facilitate efficient signal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a complex capacitor structure with multiple electrodes and wiring is used, then signal processing capability is improved, but process stability deteriorates
Solution Approach 1:
The capacitor structure is segmented into multiple independent capacitors (first capacitor between first lower electrode and first upper electrode, second capacitor between first lower electrode and second upper electrode) with distinct electrode arrangements. This segmentation allows each capacitor to be optimized independently while maintaining overall process stability through standardized fabrication processes.
Solution Approach 2:
The patent transitions from planar capacitor structures to three-dimensional stacked electrode configurations. The first upper electrode and second upper electrode are positioned at different heights above the first lower electrode, creating vertical stacking that increases signal processing capability without proportionally increasing process complexity.
2Productivity
If multiple metal layers and capacitor layers are added, then signal transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The first metal layer and second metal layer are merged into a single conductive structure that serves multiple functions: it forms the first upper electrode, second upper electrode, and provides wiring connections. This merging reduces the number of separate fabrication steps while maintaining signal transmission efficiency through the multi-electrode configuration.
Solution Approach 2:
The capacitor layer structure serves multiple functions simultaneously: it provides signal transmission pathways through the metal layers, stores electrical charge through the capacitor structures, and enables global shutter functionality through the specific electrode connections. This multi-functionality reduces overall device complexity by eliminating the need for separate components.
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 design enhances the stability and efficiency of the image sensor's signal processing, improving the overall performance by ensuring consistent and reliable operation, particularly in supporting global shutter functionality for reduced image distortion.
Implementation Method 1
Each of the pixels may include, for example, a photo diode (PD). The photo diode may serve to convert incident light into electrical signals.
Data Source
AI summary
An image sensor includes: a substrate including a first surface and a second surface on which light is incident, the second surface being opposite to the first surface; a photoelectric converter provided in the substrate; a first metal layer provided on the first surface of the substrate; a second metal layer provided on the first metal layer; and a capacitor layer provided between the first metal layer and the second metal layer, wherein the capacitor layer includes: a first lower electrode electrically connected to the first metal layer, a first upper electrode electrically connected to the second metal layer, a second upper electrode spaced apart from the first upper electrode and electrically connected to the second metal layer, a first capacitor provided between the first lower electrode and the first upper electrode, and a second capacitor provided between the first lower electrode and the second upper electrode.