Stacked Image Sensor Barrier Layout for Light-Shielding Shorts
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Solution Overview
Problem
In stacked image sensors, the light-shielding layer can cause unstable operation due to potential variations and short circuits with the wiring layer, leading to electrical connections that affect the circuit's stability and image quality.
Innovation Solution
The imaging device incorporates a light-shielding film positioned above an intermediate layer with aluminum conductive lines and a barrier layer, preventing contact between the conductive lines and the light-shielding film, thus maintaining signal characteristics and stabilizing circuit operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light-shielding layer is positioned close to the wiring layer to reduce device thickness, then the device structure is more compact, but potential variations and short circuits occur between the light-shielding layer and wiring layer
Solution Approach 1:
An intermediate layer is introduced between the light-shielding film and the aluminum conductive line to prevent direct contact. This intermediate layer acts as a mediator that eliminates the risk of short circuits while allowing the light-shielding film to remain positioned close to the conductive line, thus maintaining compact device structure while improving reliability
Solution Approach 2:
The space between the light-shielding film and aluminum conductive line is segmented by introducing the intermediate layer. This segmentation physically separates the two layers that could potentially cause short circuits, allowing them to be positioned close together without direct contact, thereby resolving the contradiction between compactness and reliability
2Reliability
If the light-shielding film is positioned above the intermediate layer to prevent short circuits, then circuit stability is improved, but the device structure becomes more complex
Solution Approach 1:
The intermediate layer serves multiple functions simultaneously: it acts as a barrier to prevent short circuits between the light-shielding film and aluminum conductive line, provides structural support, and maintains the compact positioning of layers. This multi-functionality reduces the need for additional separate layers, thereby limiting the increase in device complexity while achieving improved circuit stability
3Use of energy by moving object
If aluminum conductive lines are used in the intermediate layer for low resistance, then power supply efficiency is improved, but contact with the light-shielding film causes potential variations and short circuits
Solution Approach 1:
The intermediate layer is positioned between the aluminum conductive line and the light-shielding film to prevent direct electrical contact. This allows the aluminum conductive line to maintain its low resistance property for efficient power supply while the intermediate layer acts as a mediator to prevent short circuits and potential variations, thus resolving the contradiction between energy efficiency and electrical stability
Data Source
AI summary
An imaging device includes a pixel section including pixels, a peripheral circuit section that is provided around the pixel section and that includes a peripheral circuit, and an intermediate layer that extends across the pixel section and the peripheral circuit section. The peripheral circuit section includes a light-shielding film located above the intermediate layer, at least one first conductive line that is located in the intermediate layer and that contains aluminum, and at least one barrier layer located between the at least one first conductive line and the light-shielding film.